Added localstorage save + read
Various bug fixes

- Added missing files from previous commit
- Fixed move cursor that would remain after using a Selection tool
- Switched to mousedown for Tool Selection to avoid missed clicks
Feature : Saved status and warning msg

Added saved status (*) next to title when a Piskel is updated.
Upon saving, the * disappears.

If the workspace contains an unsaved piskel when leaving the application a
message will be displayed to the user, using onbeforeunload.

This logic should also be used everywhere we display a confirm message
before a navigation.
Added comment
Increased timeout config for Remote build
Added private rule to gitignore
UI : update display of palette tool icons
UX : Primary/Secondary colors usability

- Added swap colors icon
- Created SVG icon, source is in resources (Inkscape)
Merge pull request #153 from juliandescottes/feature-local-storage

Feature local storage