[TIMOB-18215] DOMNodeList Refactor

Previously all NodeProxies in the list were created at the same time as
the NodeListProxy. Now the NodeProxies are only created when accessed
via the item method
[TIMOB-18215] Avoid nodeListProxy creation

NodeListProxies are now only created in the public JS facing side
methods.
[TIMOB-18260] Override windowWillClose

Resign first responder on windowWillClose
[TIMOB-18260] Override windowWillClose

Cleanup _headerViewProxy and _footerViewProxy on windowWillClose
[TIMOB-18260] Signal windowWillClose before dismissal
Create .travis.yml
Downgrade to API level 17
Merge pull request #6510 from vishalduggal/timob-18215-t2-35X

CR and FT passed.
Merge pull request #6514 from vishalduggal/timob-18260-35X

CR and FT passed.
Merge pull request #6515 from appcelerator/travis

[TIMOB-18266] Add travis builds
[TIMOB-17924] Updated debugger library
Merge pull request #6519 from pec1985/TIMOB-17924-3_5_X

[TIMOB-17924] 3.5.x Updated debugger library