Quick fix for CDH4 / MRv2.

This adds a -hadooplib command-line switch to tell dumbo where
hadoop-streaming.jar is stored, along with an addition to the jar search path.
It also uses 'hadoop fs' instead of 'hdfs dfs' since it's easier to find.
Don't require -hadooplib.

This should still work for CDH3 where you don't need a separate -hadooplib.
add libdirs parameter to findjars function
simplify/cleanup listing code in cat function
version bump
Fix #60 Added cleanup functionality
Merge pull request #61 from mshevelev/cleanup

Fix #60 Added cleanup functionality
add "combined" option to dumbo cat

closes #67
Revert "add "combined" option to dumbo cat"

This reverts commit d9bbc2c86932e4dfb55e3683daaab6acbcfc477c.
add "combined" option to dumbo cat, 2nd attempt

closes #67
Fix JoinKey sort order and allow comparison with other types.
Catch too many or too few outputs with mapredtest.

mapredtest was only iterating over the actual output, silently ignoring any
further expected output.  In the extreme case, a mapper or reducer that output
nothing would always pass.  The error when a map/reduce did not produce enough
output was also not helpful.  This patch factors iterator comparison into a
function to reduce duplicated code, and adds and corrects tests.