Changelog for curry-base-1.1.1

Change log for curry-base

Added new operator @> to return the left operand with the source code position obtained from the right operand.
Parenthesized type expressions are now represented accordingly in the abstract syntax tree
Derive Show and Read instances also for identifiers to facilitate debugging and reading/writing from/to files
Emitted FlatCurry files now contain newlines to improve readability for humans
Implemented pretty printer for extended FlatCurry
Added syntax extension ExistentialQuantification that allows the use of existentially quantified types in data and newtype constructors
Representation for spans (start and end position) added

Introduced new representation of AbstractCurry
- AbstractCurry files now contain version information
- support for new record syntax
- support for newtype declarations
- evaluation annotations removed
- arity of constructor declarations removed
- simplified representation of function rules
- String literals added
Removed support for Curry's record syntax and introduced Haskell's record syntax instead
Lexer is now capable of lexing binary integer literals, for instance 0b101010 or 0B101010 can now be lexed and are converted to 42.
Removed record type extensions
Moved CYT monads to curry-base (Curry.Base.Monad) and removed MessageM monad
Adapted Curry syntax and parser: Now declaration of operator precendence in declarations of infix operators is optional
Moved module InterfaceEquivalence (curry-frontend) to Curry.Syntax.InterfaceEquivalence (curry-base)
Removed module Curry.Base.Equiv
Replaced module Curry.ExtendedFlat.Interface.Equality by Curry.ExtendedFlat.InterfaceEquivalence using a type class to implement equivalence of FlatCurry interfaces
Removed file name extensions for FlatCurry XML files.
Added syntax extension NegativeLiterals to translate negated literals into negative literals instead of a call to Prelude.negate and Prelude.negateFloat, respectively.
Added CYMAKE to the list of recognized tools when parsing an options pragma ({-# OPTIONS_CYMAKE opt1 opt2 ... optN #-}).

Updated internal structure of Curry.Base.Filenames and Curry.Base.PathUtils.
Fixed bug in parser which complained :-> expected when it really looked for :>.
Make library compile under GHC 7.8 without warnings.
Unliterating and lexing/parsing of source files are now decoupled to support custom preprocessors.
Split Curry.AbstractCurry and Curry.FlatCurry into two modules .Type and .Files, where .Type now only contains the type definition while .Files contains read/write functions. Both are subsumed by the parent modules Curry.AbstractCurry and Curry.FlatCurry for convenience.

Implementation of module pragmas added. Module pragmas of the following types are now parsed and represented in the abstract syntax tree:
```
{-# LANGUAGE LANG_EXT+ #-}
{-# OPTIONS "string" #-}
{-# OPTIONS_TOOL "string" #-}
module Main where
```
where
- LANGEXT+ is a non-empty, comma-separated list of the following language extensions: AnonFreeVars, FunctionalPatterns, NoImplicitPrelude, Records
- TOOL is either KICS2, PAKCS, or some other tool, represented as Unknown String.
Note that, naturally, the curry-base library only recognizes the above mentioned pragmas, while the processing is up to the respective tool.

All other texts given in the pragma braces is ignored and treated as a nested comment.
Reactivation of Curry interface files. During adaption of the MCC frontend to FlatCurry the Curry interface files have been deactivated and replaced by FlatCurry's interface files. To allow the later addition of type classes to Curry, they have now been reactivated.

The parser now takes the layout into respect when parsing the import list. This fixes issue #494 where a module with imports without restrictions, directly followed by an operator definition, could not be parsed.
Various internal improvements.

Support for typed FlatCurry expressions added. Now additional type information given by the programmer as in
```
null (unknown :: [()])
```
is represented in FlatCurry and cann therefore be processed by other programs like PAKCS or KICS2.

Fixed a bug where character constants not contained in the ASCII alphabet were translated incorrectly.

Made compiler messages comparable to allow later sorting of compiler errors and warnings to present them in the order of their occurence.

Improved pretty-printing of warnings and errors.
Improved error message for missing precendence after fixity declaration.
Changed syntax of records to allow disambiguation of record selection and case branches.
Various improvements.

Improved support for anonymous identifiers (test predicate, parser also returns source code position).