#252921 by David_Rothstein and agentrickard: remove unused join, which caused column type compatibility problems with postgresql; improves postgresql compatibility.

#232037 by pwolanin: (performance) block regions should only be populated when called for, not in all cases (fixes performance expectation on 403/404 pages)

#157652 by beginner, Steven Merrill and killes: block_user() had a global user object and a user parameter colliding

Backport from HEAD.

Backport from HEAD.

#100516: CSS preprocessor to cache and compress all .css files. Benchmarks show up to 40% faster page loads.

- Patch #92992 by webchick and neclimdul: clean up documentation that is superseded by the new 'by module' administration dashboard.

- Patch #63267 by profix et al: trim the content of the 'pages' setting so it can be evaluated properly.

- Patch #87057 by chx and profix898: fixed problem with not being able to configure blocks per theme.

- Patch #77924 by RobRoy: fixed race condition in block administration that might have caused data loss.