Inventory and evaluate merge of refactoring done for haiti instance

[springmeyer]

At http://bitbucket.org/springmeyer/ogcserver the ogcserver code was refactored in a hurry and unfortunately many changes, although improvements to previously broken behavior, are brittle and need cleaning up and review.

All these changes were merged in 25f4111

They include:

1. Extended the wsgi.py to support reading directly from an xml (skipping config), as well as other subtle options (these need ported to mod_python and cgi/fcgi impl) like default HTML response.

2. Better GetCapabilities support for various clients, even broken ones (we need more tests for these)

3. Switched to using WMS 1.1.1 as default if no version was requested (this avoided breaking GetCaps for old clients that never report version because they only support 1.1.x)

4. Added more thorough unicode support to GetCaps

5. loosened strictness of parameters such as format, transparent, and exceptions in terms of case and existence

6. added preliminary support for Mapnik2 if installed, otherwise we default to mapnik1

7. added strict dependency on lxml, because otherwise GetCaps will not work

8. added png8 (aka png245) request type, needs cleanup

9. switched ordering of layers to be correct to the WMS standard in terms of rendering order (this breaks many clients that do not request the right order in GetCaps and needs more work/testing) - it was originally done to support QGIS 1.5

10. added draft support for "meta layers" where groups of layers are constructed (and can be requested as one) if the styles rules are named (this was a quick hack and needs to be either removed or abstracted into a config file)