CPU only tests

[kloudkl]

To enable running the tests on machines with only the CPU, the GPU related codes have to be separated.

Related issue: #468

[Yangqing]

Could you return this to the original one-line format?

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Namespaces

[Yangqing]

Looks good to me, thanks for cleaning the CPU and GPU test :)

[Yangqing]

Since we tend to stick to the Google style guide, kindly rename this to

static bool g_curand_availability_logged = false;

and likewise below.

[kloudkl]

Both issues have been fixed. Ready to be merged.

[Yangqing]

@shelhamer Once the coldbrew master agrees, let's merge :)

[shelhamer]

Why was this test dropped? the recovered_value test that follows is the one actually checking the sync, and the memset should always succeed, but tests are tests.

[shelhamer]

@kloudkl thanks for separating the tests. I had one trivial comment, and once that's addressed we'll merge.

Thanks for pointing out this PR @Yangqing.

[kloudkl]

@shelhamer, the memtest issue is resolved. Please review again. Thanks!

[shelhamer]

Thanks @kloudkl! ./build/test/test_all.testbin --gtest_filter=*CPU* runs only CPU tests.