[PATCH] Add a 'SQLite' dialect

[Even Rouault]

This patch adds a 'SQLite' dialect, alternate to the OGRSQL default dialect, that uses the SQLite engine (when available), potentially with Spatialite extensions. This is usable for any OGR datasource.

[Even Rouault]

Core stuff committed in r24813 :"ogr/ogrsf_frmts/generic/ ogr/ogrsf_frmts/sqlite/ ../autotest/ogr/ogr_sql_sqlite.py -m "OGR: Add a 'SQLite' dialect for SQL queries submitted to ExecuteSQL() (#4782)""

Documentation still needed

[Even Rouault]

r24814: SQLite dialect: fix compilation problem with ancien sqlite lib (#4782)

[Even Rouault]

r24819 : Make VirtualOGR a loadable sqlite3 extension when SELECT load_extension("libgdal.so"); (#4782)

[Even Rouault]

r24824 : SQLite: fix Windows build with amalgamation sqlite and make VirtualOGR extension dynamic loading actually work on Windows (#4782)

[Even Rouault]

r24828: VirtualOGR: make all result string/blob TRANSIENT to avoid memory issues when rows are collated

r24830 : SQLite dialect: allow refering layers from other datasources with the same syntax as in OGR SQL

[Even Rouault]

r24831: Re-apply r24828 that was lost due to a merge issue

[Even Rouault]

r24833: SQLite dialect: add support for OFTDateTime/OFTDate/OFTTime

r24837: SQLite dialect: less false positive detection of layer names

r24838: SQLite dialect: add documentation

[Even Rouault]

There have been later commits. But everything required is in place. Closing