Merge pull request #14 from m1ch1/master

Add more details to the spec
Clean up the code.

Since now the design of Pulsed has significant changes from previous,
clean up the unused code.
Merge pull request #13 from EasonLiao/master

Clean up the code.
Context should be passed to command.
Make StateMachine an inner class of Pulsed.
Add servers handler for Pulsed.

1. Client can retrieve the active members, cluster members, leader of
the cluster.
2. Client and remove the server from the cluster.
Merge pull request #15 from EasonLiao/master

Client can retrieve cluster information
Implement DataTree and DataNode.

Without ephemeral nodes support.
Implement Create/Mofify/Sequential node.
Add LICENSE header to source files.
Merge pull request #20 from EasonLiao/dev

Create/delete/modify tree nodes
Put metadata in headers of HTTP
Merge pull request #21 from EasonLiao/dev

Put metadata in headers of HTTP
Add checksum to node
Merge pull request #23 from EasonLiao/checksum

add checksum?
Add an optional parameter to list directory recursively.

e.g. GET /dir?recursive HTTP/1.1

HTTP/1.1 200 OK
Date: Wed, 03 Dec 2014 19:54:39 GMT
version: 6
type: directory
path: /
Content-Length: 942
Server: Jetty(9.2.z-SNAPSHOT)

{
  "session": -1,
  "path": "/",
  "children": [
    {
      "session": -1,
      "path": "/dir",
      "children": [
        {
          "session": -1,
          "path": "/dir/0000000000000000000",
          "type": "file",
          "version": "0"
        },
        {
          "session": -1,
          "path": "/dir/0000000000000000001",
          "type": "file",
          "version": "0"
        },
        {
          "session": -1,
          "path": "/dir/0000000000000000002",
          "type": "file",
          "version": "0"
        },
        {
          "session": -1,
          "path": "/dir/0000000000000000003",
          "type": "file",
          "version": "0"
        },
        {
          "session": -1,
          "path": "/dir/0000000000000000004",
          "type": "file",
          "version": "0"
        }
      ],
      "type": "directory",
      "version": "5"
    }
  ],
  "type": "directory",
  "version": "6"
}
Add checksum in response header/json
Merge pull request #22 from EasonLiao/dev

List children recursively
Implement watches.
Merge pull request #24 from EasonLiao/watch

implement watch