added changelog for 0.4.0+
added changelog for 0.4.0+

snowyu/node-nosql-leveldb,mafintosh/leveldown-prebuilt,Level/leveldown,juliangruber/a-native-module,juliangruber/a-native-module,djchie/levelup,roppa/levelup,jhead/leveldown,No9/leveldown,timkuijsten/levelup,jhead/leveldown,phillipj/leveldown,timkuijsten/leveldown,MathieuCassagne/leveldown,jmanero/flat-rocks,juliangruber/a-native-module,chjj/rocksdown,Level/leveldown,timkuijsten/leveldown,jhead/leveldown,ralphtheninja/leveldown,gastrodia/leveldown,snowyu/node-nosql-leveldb,Level/leveldown-mobile,roppa/levelup,JTKnox91/levelup,jhead/leveldown,timkuijsten/levelup,snowyu/node-nosql-leveldb,lastguest/levelup,juliangruber/a-native-module-without-prebuild,Level/levelup,chjj/rocksdown,jmanero/flat-rocks,juliangruber/a-native-module,MathieuCassagne/leveldown,chjj/rocksdown,ralphtheninja/leveldown,juliangruber/a-native-module,Level/leveldown-mobile,gastrodia/leveldown,Level/rocksdb,snowyu/node-nosql-leveldb,ralphtheninja/leveldown,Level/leveldown,jmanero/flat-rocks,No9/leveldown,timkuijsten/leveldown,ralphtheninja/leveldown,toddself/levelup,juliangruber/a-native-module-without-prebuild,juliangruber/a-native-module-without-prebuild,juliangruber/a-native-module-without-prebuild,phillipj/leveldown,Level/leveldown-mobile,timkuijsten/leveldown,MathieuCassagne/leveldown,snowyu/node-nosql-leveldb,jmanero/flat-rocks,juliangruber/a-native-module-without-prebuild,lastguest/levelup,djchie/levelup,jmanero/flat-rocks,mafintosh/leveldown-prebuilt,gastrodia/leveldown,Level/rocksdb,toddself/levelup,phillipj/leveldown,Level/leveldown-mobile,Level/leveldown-mobile,gastrodia/leveldown,JTKnox91/levelup,mafintosh/leveldown-prebuilt,phillipj/leveldown,No9/leveldown,No9/leveldown,mafintosh/leveldown-prebuilt,phillipj/leveldown,chjj/rocksdown,MathieuCassagne/leveldown,MathieuCassagne/leveldown,Level/rocksdb,timkuijsten/leveldown,No9/leveldown,ralphtheninja/leveldown,jhead/leveldown,gastrodia/leveldown,mafintosh/leveldown-prebuilt