* add unit test for create_tensor passing in buffer to output tensor

* add comments

* disabled gpu create tensor unit test

* change float comparisons from == to all_close_f

* style

* address a few more direct float comparisons

* add missing include

* specify tightest tolerance for Broadcast and Reshape tests

* Increased tightness of float testing

Increased tightness of float testing via MIN_FLOAT_TOLERANCE_BITS parameter

* style

* add copy_from on GPUTensor

* add test

* remove unused code in test

* fix warning

* fix type

* fix comment texg

* using all_cloase for test

* add unit tests for the two versions of Backend create_tensor

* disable new unit test on GPU until we have time to address it