Remove `grunt` install script
Remove `grunt` install script

- New release strategy [#508] handles this now
- To use melonJS as a node module, we can publish the release tags to npm

TukekeSoft/melonJS,melonjs/melonJS,rlugojr/melonJS,gopalindians/melonJS,gopalindians/melonJS,srbala/melonJS,rlugojr/melonJS,rlugojr/melonJS,gopalindians/melonJS,srbala/melonJS,TukekeSoft/melonJS,srbala/melonJS,TukekeSoft/melonJS,melonjs/melonJS