minor cosmetic tweaks
Implemented technique to convert field dtypes to ND-arrays
test for structs and related fixes
changelog entry

[ci skip]
Py 3.x fix
Add matrix input tests
switch from erfa_time to erfa
massage cal2jd tests to be syntax-compat w/ erfa

but still fails (now xfail) due to different error/warning behavior
Add a bit of background info to erfa_time.py
Simplify ctype_to_dtype conversion dict
New Argument parsing

Added `is_ptr`, `shape`
Updated ctype_ptr()
Added name_in_broadcast and name_ou_braodcast properties
Completed Return argument with name_out_broadcast and shape attributes
Small code simplification
Made cfunc a single line
Removed not needed anymore search flags
Add Return argument is C function does not return void
Add NpyIter handling to template
Structures are in erfam.h, functions in erfa.h