Vizier doc: revert ROW_LIMIT to 50 after unlimited example
Vizier doc: updated Vizier.query_region to reflect the use of astropy.coordinates.Angle
Fixed a mistake handling box keyword in Vizier.query_region.
Vizier doc: fix documentation for use of ICRS instead of ICRSCoordinates
Vizier doc: refelct the fact that parsing string coordinates is now properly handled in astropy 0.3
Vizier doc: removed outdated documentation.