rename remoteFetchWaitTime to fetchWaitTime, since it also includes time from local fetches
enable task metrics in local mode, add tests
add a small wait to one task to make sure some task runtime really is non-zero
increase sleep time
Send block sizes as longs.
More quickly call close in HadoopRDD.

This also refactors out the common "gotNext" iterator pattern into
a shared utility class.
Forgot equals.
Remove NextIterator.close default implementation.
Merge pull request #518 from woggling/long-bm-sizes

Send block sizes as longs in BlockManager updates
Fix broken link in Quick Start.
Fix another broken link in quick start.
Merge pull request #523 from andyk/master

Fix broken link in Quick Start
Add NextIterator.closeIfNeeded.
Add a test for NextIterator.
Fix broken link to YARN documentation.
Simplify SubtractedRDD in preparation from subtractByKey.
Merge pull request #524 from andyk/master

Fix broken link to YARN documentation
Merge pull request #521 from stephenh/earlyclose

Close the reader in HadoopRDD as soon as iteration end.
Finished subtractByKeys.
Allow subtractByKey's other argument to have a different value type.