Tweaking uglifyjs command line

- mangling and compressing
- providing a sourcemap
- providing a npm task to release and publish code
Including sourcemap file as well
Fixing a typo (should have raised a test error?)
Merge pull request #78 from oncletom/feature-78

[READY] Compression and mangle options for uglifyjs when building
Fixing an `Array.prototype.map` in tests breaking w/ IE8.
Updated npm packages and dist versions of Imager.