Fixes Issue #55 - Incorrect XML comments for CollectionAssert.IsSubsetOf

I modified the summaries and parameters for all of the CollectionAssert.IsSubsetOf and IsNotSubsetOf methods.
Fixes Issue #55 - Incorrect XML comments for CollectionAssert.IsSubsetOf

I modified the summaries and parameters for all of the CollectionAssert.IsSubsetOf and IsNotSubsetOf methods.
Merge branch 'master' of https://github.com/rprouse/nunit-framework

Conflicts:
	src/framework/CollectionAssert.cs
Fixed merge conflicts from ammend
Merge pull request #72 from rprouse/master

Fixes Issue #55 - Incorrect XML comments for CollectionAssert.IsSubsetOf