Fix Memcached instrumentation
Search Rails/Sinatra application paths for config/log.
We only want this root if it exists.

We only want this root if it exists.
Reduce transient object allocations in RUM obfuscation

Also, fix RUM autoinsertion performance tests
RUBY-1324 Add failing test for this bug.
RUBY-1324 CrossAppTracing.start_trace() now takes a start time, rather than returning one.
RUBY-1324 Thread-local access cleanup, while I'm in the neighborhood.
RUBY-1324 Cleanup: Since the slow versions of TracedMethodStack's push/pop_frame were only
used in a few tests, just go ahead and convert to the fast (non-thread-local-
accessing) versions and delete the slow ones.
RUBY-1324 Additional logging in CrossAppTracing#start_trace.
Add extra logging around obscure Agent#connect() exceptions.
README updated for 3.9.0
Merge pull request #634 from ruby-agent/readme-updates-390

README updated for 3.9.0
Remove THREAD_LOCAL_ACCESS comments from places where we don't want further
refactoring, and thus have no need of the comment.
Small change from code review.
Merge pull request #635 from ruby-agent/RUBY-1324-cross-app-metric-spikes

Fix for RUBY-1324: Cross-app metrics occasionally spike
Merge pull request #632 from ruby-agent/faster-obfuscator

Reduce transient object allocations in RUM obfuscation
Merge branch 'release' into dev
Revert change to use pack('m0') in RUM obfuscator - doesn't work in 1.8.x
Merge pull request #637 from ruby-agent/revert-rum-obfuscator

Revert change to use pack('m0') in RUM obfuscator - doesn't work in 1.8.x
Merge pull request #629 from ruby-agent/search_app_paths

Search app paths