[Cmake] HIP/CUDA/OpenCL on AMD and NV support through CMake

[noelchalmers]

Description

This PR adds HIP and OpenCL builds on AMD and NV machines, as well as fixes some CUDA build issues when cuda libraries are installed in different locations. Tested:

HIP/OpenCL with ROCm 3.3 on MI-60
HIP/CUDA/OpenCL with CUDA 9.0 in /usr/local/cuda on TitanV
CUDA/OpenCL with CUDA 9.1 installed through apt on GFX 1070.

[codecov]

Codecov Report

Merging #323 into master will decrease coverage by 0.15%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #323      +/-   ##
==========================================
- Coverage   75.32%   75.17%   -0.16%     
==========================================
  Files         282      282              
  Lines       19276    19489     +213     
==========================================
+ Hits        14520    14651     +131     
- Misses       4756     4838      +82     

Impacted Files	Coverage Δ
include/occa/tools/json.hpp	54.31% <0.00%> (-6.27%)	⬇️
src/c/types.cpp	83.03% <0.00%> (-2.07%)	⬇️
src/lang/transforms/builtins/dim.cpp	78.35% <0.00%> (-1.65%)	⬇️
src/lang/qualifier.cpp	72.41% <0.00%> (-1.28%)	⬇️
src/lang/primitive.cpp	24.89% <0.00%> (-1.03%)	⬇️
src/lang/specialMacros.cpp	57.62% <0.00%> (-0.85%)	⬇️
src/lang/modes/serial.cpp	56.28% <0.00%> (-0.63%)	⬇️
src/lang/statement/blockStatement.cpp	86.33% <0.00%> (-0.54%)	⬇️
src/lang/preprocessor.cpp	72.69% <0.00%> (-0.47%)	⬇️
src/lang/operator.cpp	93.00% <0.00%> (-0.44%)	⬇️
... and 25 more

[dmed256]

🔥 Awesome, thank you for the CMake update!!