Updated method_spec to test additional java_signature return types

Added new specs to validate java_signature returning the correct java form:
  When using primitive arrays as a return type
  When using collections with generics as a return type
Don't push gem from maven?
Remove jruby-jars from pushing as work around by removing it from release since I cannot figure how to turn off the push
do not push jruby-jars gem via maven [skip ci]
trick maven to attach javadocs [skip ci]
Bump for release of readline
IT HAS BEGUN!

Remove 1.8 tests and stdlib and start migrating boot logic toward
a single runtime compatibility mode.
Eliminate calls to Ruby.is1_8 and is1_9.
Oopsed one line that should not be there for 1.9+.
Remove some remaining version-switching nuggets.
Revert "Move exitedException capture above other logic, to ensure it sets."

This reverts commit be4d7212a1bc7e5d516d7d1d6f757d3b34d8d8cd.
Revert "Always log unhandled exceptions in threads."

This reverts commit 79423216e3aa3ed0dc377aa1998471be02845613.
Remove --<version> flag from mspec runs.
make sure we have sources and javadocs files in place where needed for sonatype.

jruby, jruby-stdlib, jruby-noasm use empty jars for that since they do have no sources.

the jruby-complete sources and javadocs files will be copied from jruby-core.

make sure the jruby-dist-src can build 'mvn -Prelease' without errors.
Move to 2.0 versioning and line up tests.
Get all suites in test:extended passing.
Unify spec tags and get rubyspec passing under 2.0 mode.
update jruby-head on travis after a successful build
Return if we can’t get proper native handle.

This avoids a ArrayIndexOutOfBoundsException in case we got invalid
native handle. The program will still die, but it will now instead
return

  java.lang.RuntimeException: C extension initialized against invalid ruby
  runtime

as error.
Tidy up spec run in travis a bit.