#376129 by boombatower, Damien Tournoud, and chx: Change getInfo() to a static method to reduce memory footprint of SimpleTest.

#88264 by Rob Loach and kscheirer: Make variable_get()'s defaultparameter default to NULL so that NULLs do not need to be specified.

- Patch #346285 by grendzy, Damien Tournoud, thekevinday et al: fixed problem when HTTP_HOST is not transmitted.

- Patch #327269 by c960657: when drupal_page_cache_header() compares the client's If-Modified-Since header to $cache->created, it assumed a certain date format.  However, HTTP/1.1 allows several variations of the date format, i.e. the same time may be represented in slightly different ways. If the client sends the date in a different format than the one generated by Drupal, it would never receive a 304 Not Modified response.  Also added a good amount of tests for the drupal_page_cache_header() code.

- Patch #330582 by Darren Oh, c960657 et al: better API for retrieving HTTP headers and working with HTTP headers in tests.

- Patch #323474 by Dave Reid and catch: hook_boot() was not invoked on uncached page views if cache mode is aggressive.

- Patch #276581 by catch: wrote missing tests for contact module and simplified contact module thanks to that.  Also removed some whitespace.

- Patch #258397 by R.Muilwijk and myself: IP address detection improvements.  Added support for clusters and wrote various IP address related tests.