Add link to suggested build environment to README
Merge pull request #603 from wjordan/patch-1

Add link to suggested build environment to README
Add test for ruby-build definitions
Support changing RUBY_BUILD_ROOT

This is to allow specifying an alternate path where `share/ruby-build/*`
definitions reside. Useful in tests as well.
Extra definitions paths via RUBY_BUILD_DEFINITIONS

This is a colon-separated list of directories that will get searched for
build definition in order from left to right.
Merge pull request #613 from sstephenson/definition-paths

Support extra definitions paths via RUBY_BUILD_DEFINITIONS

Closes #609
Add rbenv-install tests
Auto-discovery of build definitions from rbenv plugins

The `share/ruby-build/` directory from each rbenv plugin, if it exists,
is added to RUBY_BUILD_DEFINITIONS automatically during `rbenv install`.
add ruby-1.9.2-p330
Merge pull request #615 from hone/ruby-1.9.2-p330

add ruby-1.9.2-p330
Merge pull request #614 from sstephenson/rbenv-plugin-definitions

Auto-discovery of build definitions from rbenv plugins
Read ruby-build revision from git if available

But don't assume that RUBY_BUILD_ROOT is where ruby-build's own files
reside, since RUBY_BUILD_ROOT can be overriden with alternate definition
files location.
Faster clone of Bats in CI

Avoid cloning the whole project's history which we'll never need
Merge pull request #612 from sstephenson/git-revision

Read ruby-build revision from git if available
add jruby 1.7.14 build
Merge pull request #620 from patricknavarromahoney/master

add jruby 1.7.14 build
add jruby-1.7.15
Merge pull request #624 from chulkilee/jruby-1.7.15

add jruby-1.7.15
ruby-build 20140905
Don't log files as they're extracted from tarball

The `-v` option for tar has been here since the beginning of ruby-build,
but it's not really informative to see a list of files in the log as the
list of files is guaranteed to be the same across machines since we do
checksums.