Changelog for hexml-0.3.3

Changelog for Hexml 0.3.3 #13, allow the . character in tags and attributes 0.3.2 #10, mark the small fast FFI calls as "unsafe" (up to 10x faster) 0.3.1 #9, don't walk off the end of the character table 0.3 #8, Mac compatibility Fix a bug when parsing closing comments #7, prefix all the C functions with hexml_ 0.2 #6, remove buffer overruns #5, add lower bounds 0.1 Initial version