Fix bug in integration test.

header contains timestamp of the response, which might be different for
different requests, we shouldn't include them in comparasion.
Merge pull request #65 from EasonLiao/fix_test_bug

Fix bug in integration test.
Merge pull request #63 from EasonLiao/ephemeral

Implement session feature
Update README.md
Move tree related implementation to separate pacakge.

Because it's logical independent
Merge pull request #72 from EasonLiao/master

Move tree related implementation to separate pacakge.
Add transaction-like support to DataTree.

- This is needed to support serving batch requests(all-or-nothing)
- Like version control system, you can make changes in staging area, and
commit or abort it, before committing the changes will not be visible.
Merge pull request #74 from EasonLiao/transaction

Expose multi-op from DataTree
Reply service unavailable during quorum loss.

- Checking whether in broadcasting phase in SessionFilter and reply
service unavailable if it's not in broadcasting phase.
Merge pull request #69 from EasonLiao/quorum_check

don't serve read requests during quorum loss
Rename project name from pulsed to pulsefs.
Merge pull request #18 from EasonLiao/master

name for the project
Make session timeout configurable.

- Make its default value to 10 seconds.
Merge pull request #68 from EasonLiao/session_timeout

change default session timeout to 10 sec
Implement ephemeral file.