NEXUS-6176: Describe page reasoning.

Rendering it now as before.
Also, group imple fixed, to retain processing order
in the reasoning map.
Merge remote-tracking branch 'origin/master' into NEXUS-6176-describe-reasoning

Conflicts:
	plugins/basic/nexus-content-plugin/src/main/java/org/sonatype/nexus/content/internal/VelocityContentRenderer.java
NEXUS-6176: Applied comments
NEXUS-6176: Simplified code

Applied Stuart's comments.
Merge pull request #282 from sonatype/NEXUS-6176-describe-reasoning

NEXUS-6176: Describe page reasoning.