Add change log

CHANGELOG.md

+# Change Log
+All notable changes to this project will be documented in this file.
+This project adheres to [Semantic Versioning](http://semver.org/).
+
+## [Unreleased]
+
+## [1.0.1] - 2015-04-25
+
+### Added
+* Changelog following [Keep a CHANGELOG](https://github.com/olivierlacan/keep-a-changelog) suggestions.
+
+### Fixed
+* Parsing of some numbers (e.g. "1e-00011111111111") causing assertion (#314).
+* Visual C++ 32-bit compilation error in `diyfp.h` (#317).
+
+## [1.0.0] - 2015-04-22
+
+### Added
+* 100% [Coverall](https://coveralls.io/r/miloyip/rapidjson?branch=master) coverage.
+* Version macros (#311)
+
+### Fixed
+* A bug in trimming long number sequence (4824f12efbf01af72b8cb6fc96fae7b097b73015).
+* Double quote in unicode escape (#288).
+* Negative zero roundtrip (double only) (#289).
+* Standardize behavior of `memcpy()` and `malloc()` (0c5c1538dcfc7f160e5a4aa208ddf092c787be5a, #305, 0e8bbe5e3ef375e7f052f556878be0bd79e9062d).
+
+### Removed
+* Remove an invalid `Document::ParseInsitu()` API (e7f1c6dd08b522cfcf9aed58a333bd9a0c0ccbeb).
+
+## [1.0 Beta] - 2015-04-8
+
+### Added
+* RFC 7159 (#101)
+* Optional Iterative Parser (#76)
+* Deep-copy values (#20)
+* Error code and message (#27)
+* ASCII Encoding (#70)
+* `kParseStopWhenDoneFlag` (#83)
+* `kParseFullPrecisionFlag` (881c91d696f06b7f302af6d04ec14dd08db66ceb)
+* Add `Key()` to handler concept (#134)
+* C++11 compatibility and support (#128)
+* Optimized number-to-string and vice versa conversions (#137, #80)
+* Short-String Optimization (#131)
+* Local stream optimization by traits (#32)
+* Travis & Appveyor Continuous Integration, with Valgrind verification (#24, #242)
+* Redo all documentation (English, Simplified Chinese)
+
+### Changed
+* Copyright ownership transfered to THL A29 Limited (a Tencent company).
+* Migrating from Premake to CMAKE (#192)
+* Resolve all warning reports
+
+### Removed
+* Remove other JSON libraries for performance comparison (#180)
+
+## [0.11] - 2012-11-16
+
+## [0.1] - 2011-11-18