Issue #161 Simplify Less resources
Issue #161 Implement server side caching for generated CSS content out of some Less resource

The CSS content is generated if there is no such in the cache or re-generated when the .less file or any of its imports is updated.
Merge branch 'master' into cached-less

Conflicts:
	bootstrap-less/src/main/java/de/agilecoders/wicket/less/BootstrapLess.java
Issue #161 - Remove old classes and add a demo application uses for unit tests
Issue #161 Remove usage of obsolete classes
Merge branch 'master' into cached-less
Merge branch 'master' into cached-less
Merge branch 'master' into cached-less