Revert "Added bootstrap3 less files"

This reverts commit f55c95a16891858c0726a26ad675570137ba8a3d.
Unused import removed.
Typo.
2013 -> 2014.
Multi-tenancy files not wanted for now.
PF-491: Orderbook: sum of invoices assigned to order positions isn't calculated correctly.
Implement css class "warning" if cost2 differs from given project or customer.
.warning added.
Unused and stupid code removed.
PF-492 - Autocompletion fields: inserting values containing html escape character (double-escaping).
Merge branch 'master' of ssh://git2.micromata.de:7999/pf/projectforge-webapp into bootstrap3

Conflicts:
	src/main/java/org/projectforge/web/BrowserScreen.java
	src/main/java/org/projectforge/web/BrowserScreenWidthType.java
	src/main/java/org/projectforge/web/LayoutSettingsData.java
	src/main/java/org/projectforge/web/LayoutSettingsForm.java
	src/main/java/org/projectforge/web/LayoutSettingsPage.java
	src/main/java/org/projectforge/web/wicket/flowlayout/ComponentSize.java
	src/main/java/org/projectforge/web/wicket/flowlayout/LayoutContext.java
	src/main/resources/styles/bootstrap/accordion.less
	src/main/resources/styles/bootstrap/hero-unit.less
	src/main/resources/styles/bootstrap/labels-badges.less
	src/main/resources/styles/bootstrap/layouts.less
	src/main/resources/styles/bootstrap/reset.less
	src/main/resources/styles/bootstrap/responsive-1200px-min.less
	src/main/resources/styles/bootstrap/responsive-767px-max.less
	src/main/resources/styles/bootstrap/responsive-768px-979px.less
	src/main/resources/styles/bootstrap/responsive-navbar.less
	src/main/resources/styles/bootstrap/responsive.less
	src/main/resources/styles/bootstrap/sprites.less
	src/main/resources/styles/projectforge.less