Fix SparseLinear

Fixed an issue with SparseLinear and added a test along with a new class
SparseJacobian (for testing sparse modules)
Merge remote-tracking branch 'upstream/master'

Conflicts:
	extra/nn/test/test.lua
CUDA fixes
fix tests:
 - std and var do not have multi-dim implementations
 - do not use square matrices for tests, hides corner cases
 - randomize the size of the matrices used in tests
 - fix x:mean(dim) call to divide by the size of 'dim'.
Merge remote-tracking branch 'upstream/master'
Add extra tests for SparseLinear and fix bug where scale was not being multiplied into bias updates
Added one more test for SparseLinear
Merge branch 'master' of https://github.com/paidi/torch