Remove Closure from FileOperations API.

+review REVIEW-5165
Move Groovydoc classes to language-groovy.

+review REVIEW-5165
Change the classycle exclude for the javadoc classes from the internal package to the public to signal the cycles are in the public API.

+review REVIEW-5165
Don't need to distinguish this as jdk6 now that's our baseline.

+review REVIEW-5165
Inline interface with a hardcoded implementation and reorg to bust package cycle.

+review REVIEW-5165
Bust up package cycles in incremental compile implementation.

This makes the structure flatter than the ideal, but it will be easier to add structure now cycle detection is enabled.

+review REVIEW-5165