ENH: First round of added tests.
Merge pull request #16 from cpelley/interpolation_tests

ENH: First round of added tests.
Fix various test failures in legacy tests (i.e. not Interpolator-specific ones).
Fixed pep8 test fails introduced by pep8 v1.50.
Replaced CML
Merge pull request #19 from cpelley/interp_test_fixes_replacement

MAINT: Interp test fixes replacement
Remove duplicate validation
Fixed analysis._interpolator handling of decreasing coords.
Test fixed.
Resolve test failure introduced by 'decreasing coords' fix.