Merge branch 'release/0.43' into develop
make earth a plot opt
fix time string formatting
rename p2d script
add sublime text project file
_c_closest_ind support backward running arrays

performance hit is absolutely negligible
ST: debug -> develop refactor

also note python version
no cython bounds checking for div and magnitude
keep axis in coord slicing if picking out one point and rm_len1_mims is False
fix streamline obound1 typeo
change seed interface and supercharge cython streamline and interpolation

note that this commit changes the array layout of seeds and lines, they
are now 3 x n arrays instead of n x 3
add test_seed.py
add as_coordinates to line, plane, and volume seeds
better vector field shape detection
better matplotlib version checking
faster plane seed generating
bump version to 0.44

features: streamline, interpolation, and seed generation speed improvements
bugfix: matplotlib version checking
Merge branch 'release/0.44'