Move Identify to its own file
Disambiguate tryIdentify from doIdentify
Allow plugins 5 seconds to identify before timeout

5 seconds was chosen arbitrarily, to prevent indefinite requests. I found 350 milliseconds to be the sweet spot where some Layer Selector requests fail and some succeed, at least for AGS servers. This variable can be configured over time.
Fix invalid reference
Merge pull request #183 from steventlamb/topic/debug_identify

Topic/debug identify