support for bounding operation queue by the byte size
add separate putLock and takeLocks + test
change byte size config to long
minor fix
remove writeOpQueueFactory

for writeQueueFactory the buffer of the element is nulled by memcache
before remove is called, thus we are not able to determine the size of
element while removing, We can potentially work around this by adding a
wrapper to keep track of size but that will have its extra overhead,
Also verified from the heap dump that the growing queue was the queue
for opQueue.
review comments
add newline at the end of file
initial working version
groupBy improvements
add copyright
add checks for elements larger than capacity and account for the size of element being added
minor refactoring
paper edits
Merge pull request #393 from metamx/group-by-improvements

Group by memory usage improvements
Merge pull request #390 from metamx/bard-oome-fix

APP-2782 Bard oome fix