Make MustMatchers to be generated under org.scalatest package, and make it available under org.scalatest.matchers through alias with deprecation warning.
Removed deprecated line in generated MustMatchers.
Generate MustMatchers test under org.scalatest as well, and fixed the new failing tests.
Merge branch 'resurrect-must-matchers' of https://github.com/cheeseng/scalatest into 2.1.x
Made several tweaks to get the Scaladoc for generated org.scalatest.MustMatchers
looking good. I reworked the paragraph on deprecation, then changed the code
generator quite a bit to get it to working on Matchers.scala. Then dropped
the code gen for the deprecated MustMatchersForJUnit, and just replaced it with
an actual one. Added code gen for the org.scalatest.matchers.MustMatchers companion object
and the org.scalatest.matchers package object that has the deprecated type alias, because
it was giving me fits when it was in the regular src. Tweaked the deprecation warning
for Should/MustMatchersForJUnit.