Reduce properties for recent changes page.
Use Git recent changes instead of the RecentChanges file.

This should also help keeping the commits clean (no RecentChanges modifications).
Remove RecentChanges content. We're using the Git-based change list now. The file should remain here as part f the default set of wiki pages.
Added few extra tests to nail down issue #267 (Nested table implementation doesn't encode < character to invalid XML produced).
Move SlimClient to fitnesse.testsystems.slim.