added new version of openproject-icon-font

- uses only unpronounceable unicode chars
- more icons
- adapted all icons to new unpronounceable unicode chars
Improved usage of icon font

- added data-icon css rules to the icon classes
- replaced all 'data-icon' occurrence with the css classes
Icons for the content area

- started to use the icon font in the content area
Use new delete icon

- removed old delete icon styles
- uses new icon font for delete icon
- whitespace fixes in app/views/projects/settings/_versions.html.erb
use new quote icon
use correct time icon in sidebar
icon for clear actions

- changed to icon from icon font
removed reload icon from old application.css
fixed white space in wp index
more icons from the icon font in the content
new version of icon font

includes more icons
added css rules for new icons

uses icon from icon font for more menu
morge icons for the content
fixed watcher icon in context menu
fixed project menu toggle submenu icon

- fixed icon in context sub menu
more icon replacement; whitspace fixes
changed icons in activity and search results
cleaned up css

- removed unused rules from main menu css
- changed submenu toggler
- cleaned up some ruels
more icon stuff
improved css

- added mixins and variables file
- use mixins and variables where it is possible
- move breadcrumb and main menu css files in layout folder