sql.py: add_index_col(): Explicitly set col_info()'s caching depending on whether col_info will be changed later by add_not_null()

sql.py: DbConn.col_info(): Allow caller to specify whether query is cacheable

csv2db: Fixed bug where CREATE TABLE statement was cached, causing it not to be re-executed after a rollback due to a failed COPY FROM. Avoid re-creating the table after a failed COPY FROM, and instead just remove any existing rows.

sql.py: add_index(): Don't generate a unique name for the index because the database does that automatically

csv2db: Vacuum table instead of just reanalyzing it because for some reason reanalyzing it isn't enough to fix the cached row count (causing pgAdmin3 to report that the table needs to be vacuumed)

csv2db: Don't add indexes on the created table because they use up more disk space than the table itself and currently aren't used. (The import process adds indexes on each iteration's column subset instead.)

db_xml.py: partition_size: Turning partitioning back on (with a larger limit), since the largest datasources' temp tables are still too big

sql_io.py: put_table(): Fixed bug where if there were multiple unique constraints that were violated, only the distinct temp table for the last one would get garbage-collected

db_xml.py: partition_size: Set to sys.maxint to disable partitioning. The last bugfix, which avoided returning a large result set to the client which was never read, seems to have fixed the disk space leak, so it's worth reattempting a full simultaneous import.

db_xml.py: put_table(): Subsetting in_table: Truncate in_table when finished with it, to avoid temp table disk space leaks