Update README.md
Merge branch 'dev'

* dev: (77 commits)
  Unwrap DataSource test.
  Discourage users from turning on metrics until they do something useful.
  Add idle fill test.
  Reduce the number of filler threads ... 8 threads is too many on a hyper threaded 4-core CPU.
  Start implementing [optional] metrics for HikariCP.
  Additional connection tests.
  Add provided dependency on coda hale metrics.
  Merged #48 fix connectionTest validation
  Change defaults.
  Default minIdle the same as maxPoolSize.
  Split out stateless utility functions to reduce the weight of the HikariPool class (increases readability).
  Rename idleConnectionBag to connectionBag.
  Change connectionTimeout minimum to 250ms.
  Fix timing edge case in test.
  Check validation error
  Improve warnings for invalid configuration
  Use the DriverManager to create connections.
  Update changes.log.
  Update changes.log.
  Remove deprecated calls from tests, fix test conditions for new background fill behavior.
  ...
[maven-release-plugin] prepare release HikariCP-1.3.4
[maven-release-plugin] prepare for next development iteration
Updated properties for 1.3.4 release.
Updated examples
Change visibility.