Merge remote branch 'origin/master'
Remove spectra files.
Merge branch 'release/0.1.0'
Rename test_stack.py and resources/GS_IRS_sep9.dat.

Change "test_stack.py" to "test_stacking.py", and "resources/GS_IRS_sep9.dat"
to "resources/GS_IRS_sep9.dat".