QFS client: do not attempt to enforce i-node access on the client side, and leave the enforcement entirely to the meta server in order allow the meta server to perform effective user id remapping.
Chunk server: fix write performance regression by removing O_SYNC flag. The primary intention using this flag was to limit the number of dirty pages due to buffered writes in the os unified page cache. Apparently nowadays the O_SYNC flag has noticeable effect even with O_DIRECT flag, at least with xfs. Since the chunk files are protected by checksum the O_SYNC flag does not affect the chunk data integrity violation detection.
Remove the O_SYNC flag, and instead issue fsync() after the final chunk header write. Doing so should help to limit the number of the dirty pages due to os writes with buffered io, and reduce the probability of "missing" writes to to os caching of both the actual file data and the host fs meta data, in the event of power loss or hw/sw malfunction.
Remove obsolete sync code path.
Chunk server: add chunkServer.syncChunkHeader configuration parameter to allow to control chunk header sync.
Chunk server: allow to cancel evacuation by deleting "evacuate" file.
Chunk server: fix count space available flags update condition in StopEvacuation().
Chunk server: turn off by default sync after chunk header write, as with direct io and the chunk file rename that follows this isn't strictly required. This option is expected to be useful with buffered io.
Meta server: fix file counter update in checkpoint restore logic.
QFS client: fix recursive chmod -- ChmodR().
Qfs tool: fix recursive chmod handling with addition / removing individual mode bits.
Add references to qfs tool in sample_setup.py.  Add sample qfs tool config.
do not attempt rmdir of missing ~/qfsbase
remove unnecessary boost_regex dep for Python

The dependency causes the build to break if versioned boost
libraries are installed, e.g. libboost_regex-gcc43-mt, and the
Python client builds happily without it.
silence subdirectory printing unless VERBOSE
Qfs top level Makefile: remove python module build from debug and release build targets, and create separate python-debug and python-release targets.
Merge branch 'master' of github.com:/quantcast/qfs
Meta server: implement "range truncate" to allow to create chunk boundary aligned holes in non striped files. The primary intention is to use such truncate with write append in sorter, to allow to discard sorted chunks. Optimize meta b+tree iteration / search by avoiding redundant binary search withing terminal b+tree nodes. Optimize chunk search in truncate by performing linear search if the first chunk position (offset) is close enough (less than 8 chunks) to the target position, otherwise do b+tree search.
Meta server: eliminate compiler warning.
Meta server: fix b+tree search condition in Tree::truncate().
Meta server: do not allow any form of range truncate with striped files.
Meta server: range truncate fix right edge check.