[raster] raster2pgsql.py should not set regular_blocking to true when wildcard are used to load many rasters

[pracine]

wildcard allow us to load many rasters and it is very usefull to be able to use them with the "-k 100x100" option but there is no garantee that those many rasters will result in a coverage following rules 3 and 5 of regular blocking:

3) The top left block must start at the top left corner of the extent.

5) The extent field must be a simple rectangle (non-rotated).

It might be very difficult to verify those conditions so it might be better to set regular_blocking to FALSE when using wild card.

I saw that it is also impossible to use -k when two -r options are used. Again the rule should be that we can use -k but because there is many rasters we can not assume they will end up in a coverage following regular_blocking.

[pracine]

-Same problem when we use the -a option to append tiles to an existing table.

[dustymugs]

As regular_blocking is now an "informational" constraint explicitly set by the user, no reason for the software to make the decision.