added node-webkit to generate standalone app.
Merge remote-tracking branch 'upstream/master'
Make desktop app directory with all nedded files before build it.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Gruntfile.js
Setup nw releases destinations to build folder.
change node webkit versions to work with older node versions.
Feature : Current colors palette

Created dynamic palette displaying currently used colors.
This palette is now selected by default.

New service UsedColorsService created. Listens to PISKEL_RESET and
TOOL_RELEASED and keeps track of the list of current colors.

Still need to :
- improve sorting of colors
- allow to clone the current color palette as a custom palette
- add proper getter in UsedColorService to get the list of current colors

Also I hardcoded a max-height for the palettes-list as I found no better
way of handling the case of palettes containing many colors.

Maybe should add a limit to the number of colors handled by this automatic
palette.
Feature : Tiled preview initial commiy
Merge branch 'master' into feature-tiled-preview
TiledPreview : follow up
Tiled preview : mutualize canvas background update

When user changes canvas background, css class now applied on document
body.

Created new controller listening to Events.USER_SETTINGS_CHANGED to handle
this.
Fix : set name for tiled background checkbox
Fix : bug when setting switching primary and secondary colors
Fix : changed classnames used for primary and secondary color highlight in palette
Renamed UsedColorsService to CurrentColorsService + exposed getCurrentColors explicitly
Moved hardcoded values to constants in PaletteListController
Change node webkit releases location, ignore unecessary files.
Merge branch 'master' of https://github.com/juliandescottes/piskel
Merge pull request #178 from fsvieira/master

Standalone App with node-webkit
Merge branch 'master' into feature-dynamic-palette