Build fails due to gtest if not connected to Internet

[Prof Garth Wells]

gtest configuration needs to handle case of not connected to Internet. Possibilities are:

1. Disable gtest if not connected to Internet
2. Add gtest code to repository to remove need for build scripts to download it.

[Jan Blechta]

gtest is in <ffc>/libs/gtest-1.7.0. What about using that one?

[Martin Sandve Alnæs]

Sorry this was wrong: "That one is also downloaded, same issue."

[Martin Sandve Alnæs]

gtest is really not changing a lot, I suggest just adding it to dolfin.

[Prof Garth Wells]

I favour adding to DOLFIN. It would be strange to have FFC as a dependency to get gtest.

[Prof Garth Wells]

See #905.

[Prof Garth Wells]

Superseded by #905.