REVIEW-2061: Reduced number of changes reported for out-of-date tasks
Removed unused interface type
REVIEW-2068: Correct documentation for publishing extension
REVIEW-2070: Removed unused method
REVIEW-2090: Revert "Escape the '@' sign in javadoc examples"
- Apparently this is only required for JDK1.6 due to a javadoc bug, not required for JDK1.7 (which we use for generating javadoc for release).

This reverts commit 0c5dc690ea0deb4b8bcd1d5583bbcd5055d560fb.
REVIEW-2078: Don't load or persist history when Task.upToDateWhen is false
- Moved logging of 'out-of-date' messages out of DefaultTaskArtifactStateRepository into SkipUpToDateTaskExecuter.
REVIEW-2077: Merged TaskExecuter and ContextualTaskExecuter into a single, contextual interface
REVIEW-2083: Improvements to incremental task userguide chapter
- Switched to verb-based names for file manipulation tasks, and added a sentence clarifying what these are for (thanks, @luke).
- Added section demonstrating changed property leading to all inputs out-of-date
Removed unused LOGGER