Set $CYGWIN under cygwin.
Bundle updated.
Updated bundle.
Source /etc/environmnet if present.

Useful on Linux distros.
Set RBENV_ROOT to /opt/rbenv if present.
Merge branch 'master' into os_x

* master:
  Set RBENV_ROOT to /opt/rbenv if present.
  Source /etc/environmnet if present.
  Updated bundle.
  Bundle updated.
  Set $CYGWIN under cygwin.