Add build-log plugin

[danielbeardsley]

I can see a use for two plugins:

build-log

• Outputs a running log of build events (like the server log is now)
• Use a defined format
  • timestamp: build_id repo branch status

build-status-log

• Updates a JSON file after every build, keeping the last 3 or for builds for every branch.

  • Effectively used as a data store (bad idea?) (read in on load, written out after every build.

  • Makes it very easy to write command-line or web-based tools.

  • Contents:

    { 'http://repo-url' : {
    'branch': [
    {buildid: 23,
    started: 34626326,
    status: 'success',
    logUrl: 'http:///blah.com/log',
    buildTime: 3453},
    {buildid: 26,
    started: 34626326,
    ...}],
    'other-branch': [
    {...}]
    }}