Add simple test

[trelau]

• Use Python script to call exe for a given input file and test runtime

• Seems to work on Windows, but failing on Linux/OSX I think because the program is not being installed to the right place. Any ideas?

DO NOT MERGE UNTIL LINUX/OSX TESTS ARE RESOLVED

[Yixin-Hu]

Please try
./TetWild --input=./scratch/12246.stl --output=./scratch/12246.msh
instead of
TetWild --input=./scratch/12246.stl --output=./scratch/12246.msh

[Yixin-Hu]

Could you fix the tab error?

File "/home/travis/miniconda/conda-bld/tetwild_1531412494745/test_tmp/test/test_tetwild.py", line 41
if platform == "win32":
^
TabError: inconsistent use of tabs and spaces in indentation