Merge pull request #29 from yyyc514/master

REE should use the do not install helpful gems option
Revert "$PREFIX_PATH can be specified as a relative path"

This reverts commit 20f7b5c0e99f73164175f19eb4f6f96f560b08e5.

Conflicts:

	bin/ruby-build
ruby-build 20110906.1
Add basic rbenv-install script
Merge pull request #31 from sstephenson/rbenv-install

rbenv-install
Respect RBENV_ROOT
Show usage
Add install_git and refactor to support it. Pass package name, git url, git ref, and build commands.
Autocompletion
Merge remote-tracking branch 'jeremy/install-git'
pushd and popd are noisy
make_package should not print the "Installed" message
Pass $CONFIGURE_OPTS to ./configure
Add definition for rbx-2.0.0-dev
Merge remote-tracking branch 'guilleiguaran/rbx-2.0.0-dev'
rbx-2.0.0-dev gets rubygems-1.8.10
ruby-build 20110914
use gcc on lion for 1.9.2
Include --with-gcc config flag for gcc-4.2 on Lion, per https://github.com/ruby/ruby/commit/9151ed22b360ba3d2bde3b51969a682f9a4a3096
Merge pull request #40 from jeremy/with-gcc-flag

set --with-gcc=gcc-4.2 on lion + xcode 4.1