[FIX NW] Ext.Loader: fix loading in `node-webkit`

* optimize out needless `debugSourceURL`
* 'ext-all-nw.js': add whitespace stripped version of actually used file
* 'ext-all-dev.js': for finding and debugging framework issues
  (rename to 'ext-all-nw.js', debug, rename back)
  this file will not have thurther fixing and optimization patches
* close #3, this ExtJS 4.2 can be used now:
```sh
  > git clone ssh://git@github.com/suprojs/extjs-4.2
```
  specify that directory in 'supro/extjs.txt' and go

Signed-off-by: Oleg Verych <olecom@gmail.com>