vo: add TapQuery.waitForResultUrl async utility method
ttools: minor typos
ttools: move UploadConeTable out of CdsUploadMatcher for reuse
ttools: implement basic TapUploadMatcher

UploadMatcher implementation for TAP services.

Modes BEST and BEST_REMOTE are still not done - I don't know how
at the moment.
ttools: implement BEST find mode for TapUploadMatcher

Have to do this by client-side filtering on an ADQL ALL match -
better minds than mine (i.e. Markus) doesn't think there's any
other way.

BEST_REMOTE can't be done at all.  Provide this information in the API.
ttools: adjust ADQL for tap upload match
ttools: add TapUploadSkyMatch task

Add Task harness for the TAP upload sky match function.
ttools: fix TapUploadMatcher to cope with oversize BEST matches

Best matches are handled client-side, so the way that row limits
are implemented has be be different from other modes.
ttools: add TAP upload match column selection parameter
ttools: modify Coverage user functions

Add new function nearMoc, required to find out if a position is
within a given radius of a MOC, often more useful than whether
it strictly falls within it.  Also change the way that MOC names
are interpreted, so you can use a VizieR table ID as an alternative
to MOC FITS file URL/filename.
ttools: document tapskymatch task