ST3 compatibibility

No changes in functionality as far as I can remember. I removed `setup.py` because it's so annoying and I assumed you don't you it anymore.

The following functions were added to `sublime_lib.path`:

- get_module_path(_file_=None)
- get_package_path(_file_=None)
- get_package_name(_file_=None)

Parameters are for all functions equal: `_file_` should represent the value of `__file__` in the file you are calling it or of which you want to know the path information about. If `None` `inspect.stack()` is used to get the value from the stack frame, which should work in most cases.
The functions are compatible with ST2 and ST3 and work in archived state (`.sublime-package`). Maybe they don't have 100% accuracy for people messing with symlinks and whatnot, but I cba to maka test env for that.

The following module has been added to `sublime_lib`:

- edit.py

Provides an edit abstraction for WindowCommands that is compatible and consistent with ST2 and ST3. Originally obtained from https://github.com/lunixbochs/SublimeXiki/blob/st3/edit.py and modified. See also http://www.sublimetext.com/forum/viewtopic.php?f=6&t=12551.

There are other things that need fixing but are not in scope of this PR, so I will file them later. I'll leave the release tasks to you.

Tell me when you published the release, I will update the package control channel then.