code clean up

This pull request try to give the same coding style to all the beluga source code. You should respect this new coding style in your next commits.

The new coding style try to respect what i've seen in the Haxe std lib.

#### Summary of changes:

* remove all trailing whitespace - don't let them in the code anymore
* remove all headers - we don't care about who have made a given file, git history can tell us
* indent is made with 4 spaces
* all 2 spaces indents are now 4 spaces
* brace are next to the items not below
* useless comments are remove, dont pollute the code e.g:
```
/**
* Subscribe function
*/ 
function _subscribe(): Void;
```
this is a useless comment.
* i made the import like this : first haxe import, then beluga.core, then beluga.module. I think it's more readable.