Merge pull request #28 from thehogfather/codemirror_upgrade

Upgrade to new codemirror folding extension
version bump
update to minimum supported brackets version
Addresses issue #30 where code folding is broken after using Ctrl-Alt-- to fold current code region.
Fixed minor issue where code range opened and closed on the same line is still marked as folded when using shortcuts
addresses issue #32 where line fold state is not being correctly persisted after modifying document. Consequently restoring line folds results in wrong folded regions.
Added instruction to README to address issue #34 where keyboard shortcuts might conflict with typing non alphabetic characters on some non-English keyboards.
added menu items for collapsing and expanding code regions under view menu (addresses issue #33)
removed keybinding  (ctrl-alt-+) for expanding current code region and left (ctrl-alt-=) as per issue #34
change base key for shortcuts to letters in order to reduce chances of conflicts with international keyboards
addresses issues #34, #35 and #36
Added support for folding latex documents
fix for issue #37.
improved latex text folding
added brace folding to latex and bibtex file
(WIP) addresses issue #38 where line folds are lost when document is refreshed  programmatically (e.g. through git).
further addresses issue #38
nested folds where being unfolded when programmatically restoring line folds. Now calls to fold a region is forced when folding is explicitly required.
added support for ruby files using indent fold.
removed unused parameters in codemirror fold functions
Addresses issue #39 — indent folds is now the default for files without explicit fold helpers.
Refactored to remove references to unused properties.
Addresses issue #40
Improved indent folding
minor bug fix - addressing example .haml file presented in issue #40
bumped version number
Ending menu divider removed
unused foldgutter.css removed and main.less improved

triangles look less annoying now