Adds test from cunn and pointwise activations

[szagoruyko]

Copied cunn/test.lua and substituted cuda stuff with cl, now on Intel HD 4000:

> nn.testcl()
**_*_*_**_****_*_*__****_******_*_*_*___*_******____*****__****__**_**____________**  ==> Done Completed 52 asserts in 84 tests with 47 errors

Also as cltorch has the same apply kernels I adopted https://github.com/szagoruyko/cunn-rtc/blob/master/Pointwise.lua and easily added

• Sqrt
• Square
• Abs
• Exp
• LogSigmoid
• HadTanh

(thus removed Sigmoid.lua as it is now with Pointwise functions) Made SpatialMaxPooling accept 3D inputs on forward

[hughperkins]

Nice! :-)