read_band() delegates to read()

With the help of new io_multi* functions.

Closes #96.
Turn off array bounds checking.

Also let block_windows() default to bidx 1 when band block shapes
are homogeneous.
Test and document use of default bidx in block_windows().
Allow reprojection of multi-band arrays.

Closes #98.
Note fix of #98.
Remove debug statement.
Support for GDAL CInt16 datasets.

Closes #97.

No tests specifically for this data type. Other complex types
are TBD.
Closes #99.
The other 3 GDAL complex types.
adding support for color interpretation
write the color interpretation
add enums for colorinterp
return enum value for color interp
return colorinterp on getter method
remove return from colorinterp setter
Remove write_colorinterp().

GDAL doesn't really support in-place modification of band
color interpretation, as mentioned in #100.
Test of CMYK photometric option.
Add plt to rio_insp locals.
Add a nogil function to help async example.
Add a more notes inline.