Changed operator --> to ==>

Apparently --> would conflict with Foq, so a unit test using Foq would not
be able to use the ==> operator. Also a static Operation.applyMetaData
function is created that makes it easier for clients to create a new
operator if the build in doesn't work.
Moved example helper functions to new file

Make it easier to refactor the existing self tests
Changed selftest.fs to build examples

Instead of using the DSL to build examples, but building examples directly,
it becomes clearer what functionality is really tested, the runner, and
output reporting - and it makes it easier to ditch the old DSL.
Changed RunnerSpecs to build examples

By removing dependencies to the DSL, it makes it easier to change.
Removed DslHelper

Code ugliness gone away
Refacor example building spec code
Renamed addChildContext to addChildGroup

Should have been renamed when TestContext was renamed to ExampleGroup