Caching run results.

Conflicts:
	src/main/java/org/concordion/internal/FixtureRunner.java
Fixed 1.7v1.5 compile error
Added tests

Conflicts:
	src/test/resources/spec/concordion/results/Results.html
Made the cache handle circular dependancies and parallel runs of the same test.
Fixed compile error due to cherry pick from a branch with an additional class.