Provide TestPage to test system to test on, not PageData only.
Move Base64.java to fitnesse.util package
Move CommandRunner to fitnesse.testsystems package, since that's what it's used from
WikiPageResponder cleanup
reformat TestPage
WikiImportProperty cleanup.

Do not pass wikipage and data
TestPage: SetupTeardownAndLibraryIncluder takes only TestPage as input.
Let TestPage know about the individual pages needed to run the test.

This is some preparation to cache data in SlimTestSystem.
Removed bit f bi-directionality between fitnesse.testsystems and fitnesse.responders.run packages.
Squash! fix include arg
Removed SetupTeardownAndLibraryIncluder.includeSetupsTeardownsAndLibrariesBelowTheSuite
Renamed TestSystemListener.acceptOutputFirst to testOutputChunk
SlimTestSystem cleanup: less instance variables.
Removed SlimTestSystem.getTestResults
Merge branch 'slim_refactoring' into testcontext
Use String.replaceAll in replace method.
Handle ExecutionLog as an artifact of a test, not as a prerequisite for starting a test system
Merge SlimTestSystem.NestedSlimTestContext and MockSlimTestContext

Big rename, reduced duplication.
Let CommandRunner use BufferedInputStream. Fixed runnable class name
Remove preparsed scenario stuff, since it does not improve performance.