This patch includes:

* version column removed from modules table, now using standard config, this allows decimal version for modules
* version column removed from block table, now using standard config, this allows decimal version for blocks
* module version.php can safely use $plugins instead of module
* new plugin_manager bulk caching, this should help with MUC performance when logged in as admin
* all missing plugins are now in plugin overview (previously only blocks and modules)
* simplified code and improved coding style
* reworked plugin_manager unit tests - now using real plugins instead of mocks
* unit tests now fail if any plugin does not contain proper version.php file
* allow uninstall of deleted filters

block_xxx_pluginfile() now accepts the $options parameter that is to be passed
to the send_stored_file() function.

MDL-23234 finally standardised use of settings.php across all plugins - the only partial exceptions now are report and local plugins

MDL-20204 first batch of major theme changes, some regressions are still there, expect more changes and improvements soon; see tracker for details and list of subtasks

MDL-20700 coding style cleanup - cvs keywords removed, closign php tag removed, trailing whitespace cleanup

MDL-17458 upgrade logging implemented + a lot more refactoring + exceptions implemented in install/upgrade code + lang pack cleanup + some more improvements

MDL-17457 migrated all modules to new db/install.php; added upgrade.txt file for devs converting contrib modules