Added query class, started to mangle Posts class.
Allow single in() values to be filtered.
Allow added expressions to be named
Some basic Posts::get() queries are working now using the new Query class.
Merge branch 'master' into namedparams
Allow WHERE expressions to collapse when empty.  Support ORDER BY.
Restore some date query support to revamped Posts::get().  Allow QueryWhere to use subqueries for IN().
Starting to work on fix for #168
Fixed conflict between what I committed to trunk and had not reverse here
Merging conflicts
Merge branch 'master' of github.com:lildude/system
Merge branch 'master' of git://github.com/habari/system
Merge branch 'master' of git://github.com/habari/system
Merge branch 'master' of git://github.com/habari/system
Merge branch 'master' of git://github.com/habari/system
Merge branch 'master' of github.com:habari/system
Merge branch 'master' of github.com:habari/system
Merge branch 'master' of github.com:lildude/system
Merge branch 'master' of github.com:habari/system
Merge branch 'master' of github.com:habari/system