Upgrade CSW GetRecrod for better filtering

Upgrade CSW GetRecrod for better filtering -- 2nd try

Upgrade CSW GetRecrod for better filtering -- 3rd try (add support for the PropertyIsNull and PropertyIsNull)

change a few args name

Upgrade CSW GetRecord for better filtering
Add Not/Or/And. fes.py now implements most of the OGC 1.1.0 Filter spec.
Clean up CSW tests. Remove a 404 Google couldn't find a replacement for.
Remove two 404 tests from WFS.  fixes #49.
Remove 404 WCS test and add move its coverage to another WCS test.
Remove 404s from SOS and OWS tests. Coverage is elsewhere.
Update various sections of the code to work without LXML installed.

This is backwards compatible
Merge pull request #60 from mazl123321/csw_filter_upgrades

FES and CSW improvements.  Testing cleanup.