First release of revamped "Color Conversion Tools"

After significantly overhauling and extending the functionality of the plugin, I think it's time for a release!

The main highlights of this release are:

• Sublime Text 3 support (ST2 also still works)
• Hex-to-RGBA and RGB(A)-to-Hex roundtripping is now supported (previously only the former worked)
• Added Ctrl-Shift-H for converting from RGB(A) to Hex
• Support for converting individual "unsigned byte" values to and from float values
• Revamped menu/command access
• A few assorted bug fixes