support version 3 of gocd api

[pracplayopen]

after upgrading to latest gocd (19.4), this dashboard wrapper stopped working.

this broke the dashboard replacement. After talking with gocd, they confirmed that v1 dashboard api that worked for many years was deprecated in version 17 (in last 2 years).

after upgrading the 'dashboard.js' file to use v2/v3 gocd apis, some things worked better but pipelines sitll error.

javascript console error:

Uncaught TypeError: Cannot read property 'pipelines' of undefined
    at populatePipelineGroup (dashboard.js:61)
    at Object.<anonymous> (dashboard.js:44)
    at Function.each (jquery.min.js:2)
    at Object.<anonymous> (dashboard.js:40)
    at j (jquery.min.js:2)
    at Object.fireWith [as resolveWith] (jquery.min.js:2)
    at x (jquery.min.js:4)
    at XMLHttpRequest.b (jquery.min.js:4)