Change Error message for missing subversion

The current error message for missing subversion is "error: please install \`svn\` and try again", leading the user to try to find and install a package named "svn" (eg. `aptitude install svn for # debian / ubuntu). Changing it to "subversion" can help users unaware that svn is a binary installed by the subversion package, get through the error.
Merge pull request #669 from Zorbash/master

Mention 'subversion' in error message when svn is missing
Ignore RUBY_CONFIGURE_OPTS from environment in testing

Avoids failures caused by somebody's environment possibly having
RUBY_CONFIGURE_OPTS exported to have a value.
Fix `script/test` in a non-Travis environment

`script/test` will now only attempt to call `script/mirror` if either
TRAVIS_PULL_REQUEST or TRAVIS_COMMIT_RANGE is set.
Fix error message assertions in JRuby tests

`assert_failure` only accepts an expected message as argument, and only
if it matches the output in full.
Ensure that `assert_output_contains` receives an argument
JRuby 9000 is now 9.0.0.0 (official version number for release).
Merge pull request #672 from headius/jruby-9.0.0.0

JRuby 9000 is now 9.0.0.0 (official version number for release).
Abort with usage help on wrong number of CLI arguments

- rbenv-install accepts 0 or 1 argument
- rbenv-uninstall accepts 1 argument
- ruby-build accepts 2 arguments
Improve ruby-build test for too many arguments

Use exactly the same arguments that would have `ruby-build` succeed at
executing, but add one more extra to test argument counting.
Perform CLI argument validation as early as possible
Provide CLI usage help on stout/stderr appropriately

When requested via `-h|--help`, usage text should be displayed on stdout
and the exit status should be 0.

When usage text is shown due to invalid arguments, it should be
printed to stderr and exit status should be 1.
Extract ruby-build usage from comments like we do in rbenv
Capitalize "Usage:" header for consistency with rbenv help system
Move rbenv-install/uninstall tests to `rbenv.bats`
Have rbenv-uninstall respect `-h|--help`
Merge branch 'extra-arguments'

Fixes #667, closes #668
added definition of 2.2.0preview2
Merge pull request #678 from sstephenson/2-2-0-preview2

Added definition of 2.2.0preview2
ruby-build 20141128