add rebuild npm script
add rebuild npm script

No9/leveldown,gastrodia/leveldown,ralphtheninja/leveldown,ralphtheninja/leveldown,timkuijsten/leveldown,timkuijsten/leveldown,gastrodia/leveldown,MathieuCassagne/leveldown,juliangruber/a-native-module-without-prebuild,juliangruber/a-native-module,timkuijsten/leveldown,chjj/rocksdown,jmanero/flat-rocks,juliangruber/a-native-module-without-prebuild,ralphtheninja/leveldown,juliangruber/a-native-module,jhead/leveldown,MathieuCassagne/leveldown,phillipj/leveldown,gastrodia/leveldown,No9/leveldown,Level/rocksdb,timkuijsten/leveldown,MathieuCassagne/leveldown,No9/leveldown,jhead/leveldown,juliangruber/a-native-module,ralphtheninja/leveldown,No9/leveldown,juliangruber/a-native-module,jhead/leveldown,chjj/rocksdown,Level/leveldown,Level/rocksdb,gastrodia/leveldown,juliangruber/a-native-module-without-prebuild,phillipj/leveldown,MathieuCassagne/leveldown,jmanero/flat-rocks,phillipj/leveldown,jmanero/flat-rocks,timkuijsten/leveldown,chjj/rocksdown,chjj/rocksdown,juliangruber/a-native-module-without-prebuild,gastrodia/leveldown,Level/leveldown,Level/rocksdb,juliangruber/a-native-module,Level/leveldown,juliangruber/a-native-module-without-prebuild,No9/leveldown,jhead/leveldown,jhead/leveldown,phillipj/leveldown,jmanero/flat-rocks,MathieuCassagne/leveldown,ralphtheninja/leveldown,phillipj/leveldown,jmanero/flat-rocks