Initial implementation of Sequel instrumentation.
Add initial testing
Merge branch 'dev' into RUBY-1057
Merge branch 'dev' into RUBY-1057
RUBY-1057 added ORM agnostic mechanism for getting a database connection
Add model instrumentation, explain plans, sql param.
Merge branch 'dev' into RUBY-1057
Simplify tracer declarations in Sequel::Model instrumentation
Add some missing API docs.
RUBY-1057: Incorporate suggestions from the pull request
Merge branch 'dev' into RUBY-1057
Increasing max on Timeout for thread profiling tests

Because we poll on these, it shouldn't increase typical test run time.
This should let us know whether these tests are just getting slow responses
in CI, or whether it's just not getting back at all (if we continue to time
out)
Word the Sequel version log message to be less alarming
RUBY-1062 houseclean comments

With Sam's help, I reviewed this pull request and made
some gramatical improvements and noted one semantic ommission.
Fix a bug in the metric name on instances with a :name column (jclark)
Remove superfluous SQL debug log statement
Update to use Database.extension (3.47) instead of the lower-level hook
Bumping version for upcoming beta and release.
RUBY-1084 Report instance busy from Resque parent
RUBY-835 Don't double-count Net::HTTP requests

If the connection isn't started, Net::HTTP#request will call back into itself.
Since we instrument that method, we end up tracing twice, doubling the counts.
Don't do that.