Generated scss now contains some extra newlines

Inserting some newlines to make the beautified code a bit more readable. Right now there's only two rules where an extra newline is inserted: 
1) At the end of } (unless it's at the start of a line, sass-convert seems to separate top selectors with newline already)
2) If a lines ends with ; (indicating a property has been defined) and the next line contains { (indicating the start of a selector), then an extra newline is inserted between the two lines.
Update SassBeautify.py

Improved the rules for newline insertion, no longer produce any unnecessary blank lines.
Remember viewport position and selection on save

Added code which should restore the viewport scroll position and the selection after save, instead of scrolling to the top.
Update SassBeautify.py

Fixed so that newlines are inserted if the selector is preceded by a comment.
Comments at the end of lines preserved

Comments at the end of lines should no longer be pushed down to the next line. Fixed minor issue where newlines were not always inserted between selectors when several selectors had a comment block above. Not very tested, but it seems to work.
Optimized regex and improved newline rules.

Previous commit had slow regex replacement, should be a lot faster now. Also improved the rules when it comes to inserting newlines and when it comes to restoring comments at the end of lines. Still very much untested at this point.
Fixed Sublime Text 2 compatibility.
Cleanup and added unit tests

- Minor cleanup
- Added unit tests for the reg exp matching.
Added settings for optionally keeping comments inline and for adding a new line between selectors
Added nested selector
Updated README
Merge branch 'feature/whitespace-comments'