Potential ts.composite enhancements

[mflaxman10]

ts.scene lets you specify a point (in web mercator).

it would be very useful in scripting to have the same for ts.composite.

I think it would also be nice if this could be specified in lat/lon as well as web merc. Outside the Tesselo-verse, lat/lon WGS4 is much more common.

Also, I personally find min_date_0 and min_date_1 unintuitive names, so perhaps:
latitude = 45, longitude = -120.0, start_date = '2019-01-01', end_date = '2019-01-31'
or
northing=239023, easting=-329023 ...

Of course, to future proof, might also consider ISO date range standard which is a / separator:
2013-01-01/2013-06-31

I think this also extends to naive and time zone aware times, for when we start getting into Planet and other satellite choices with multiple options daily!