Uses users home path by default
Removes whitespace from line endings
Addds the new macosx function

The commands module is deprecated for now, but
I've not changed the old code just yet. Just the
new code.

Adds mac osx wallpaper function

This uses osascript to change the background by
telling Finder to change the background
Calls mac os x function
Adds automatic platform detection

Detects the platform

The platform is detected by sys.platform and if it
is mac os x (ie. darwin), the mac os x function is
called. Otherwise the gnome function is called.
Putting the old path back

Since this pull request is just concerned with mac
os x code, I've put the old download location back
Imports os

Forgot to import the os module
merge changes from mindriot101/macosx