Changelog for limp-0.3.2.3

0.3.2.3, 2018/11/13: * Fix pretty-printing bug: printed programs did not include final 'End' line, so cbc could not parse the programs * Relax the upper bound for containers dependency (contributed by @fumieval) * Update test dependencies * Update package description 0.3.2.2, 2018/06/04: * Build -Wall clean with GHC 8.4.3 * Relax the upper bound for base dependency * Add missing semigroup instances (contributed by @fumieval) 0.3.2.1, 2015/07/21: * Naive implementations of two solving algorithms: * Branch-and-bound algorithm for mixed programs * Simplex algorithm for relaxed (real) programs * Add tests to package description 0.3.2.0, 2014/11/02: * Error handling for simplifier 0.3.1.0, 2014/09/19: * Simplifier for Canon programs * Pretty-printer for Canon programs 0.3.0.0, 2014/09/03: * Simplify Canonical representation * Add evaluator for Program representation 0.1.0.0, 2014/06/04: * Initial release