* removed paths in include directives
* changed cmake to provide necessary header search paths
* changed name of version.h to productVersion.h due to name conflict
* Handle all error related messages in ErrorController
* Moved error filter state from Storage to ErrorController
* Moved all error related messages to type/error subdirectory
* Enable all errors shown by default
* Always show unfiltered error count in status bar and overview
* Fixed all errors shown again when changing error filter on errors for file
* Moved error filtering to PersistentStorage
* Fixed wrong error count in statusbar and dialog sometimes
* Make sure error tab is visible when showing Log View
* Don't show error view when no visible errors are added
Having only one access point to the Storage will simplify caching and parallelisation in the future. Also the two
accesses were never really independent of each other anyways, because in some cases they had to access both data sets.