Add tile and creationDate to VML features
Add SQL to create VML tables and indexes when loading via PGDump driver
Add readme and config for loading VML via PGDump driver
SQL to manage VML full tile updates
Use LIKE clause of CREATE TABLE to create update and archive tables.

Avoids using the CREATE TABLE foo AS SELECT hack for the archive tables
and greatly reduces the SQL required for the update tables.
Avoid listing columns of current tables when inserting.

Now that the update tables are generated based on the current tables
minus an ogc_fid column we can avoid listing the columns which will
hopefully aid future maintenance.
Merge branch 'vml_pg' (OS VML PGDump and Update support)