Changes to get-deps.sh to download gtest.

* get-deps.sh:
  (Variable definitions): Adds three "GTEST_*" variables to assist in
   downloading gtest sources.
  (get_gtest): New function: Download, unzip and move gtest source.
  (get_deps): Check whether gtest is available.
   Call get_gtest().

* .: Ignore the gtest directory.

Patch by: Gabriela Gibson <gabriela.gibson{_AT_}gmail.com>
          (Tweaked by me)


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1427728 13f79535-47bb-0310-9956-ffa450edef68