#JC-1869 Try to combine plugin and system permissions

Aim is a processing system and plugin permissions as one collection.
Permissions are loaded on the page, but for plugin permissions editing
is disabled because AdministrationController work with BranchPermission
only. Need to have method for finding by mask for system and plugin
permissions.
#JC-1869:Questions permissions

*Avoided generic permissions everywhere where possible. Now we use JtalksPermission interface instead of it

*Added custom Jcommune permission factory to process standart and plugin permissions

Added plugin permissions factory to process plugin permissions

*Now permissions from plugins can be listed and changed via edit permissions dialog

Corrected unit tests

Seems like some refactoring will be needed
#JC-1869:Questions permissions:
*Fixed mistake with loading non-enabled plugins
*PluginPermissionFactory now initialize only one time
#JC-1869:Questions permissions:
*Plugin logic replaced into separated module
*Added NullPermission to handle permission from removed plugins
[JC-1822][JC-1874] Correction of untranslated english messages in
Spanish properties. Maintenance of the spanish properties with new
additions. Modification of the entrance label.login_error in all
languages according to the given texts in [JC-1874].
JC-1874 Fixed typos in login error labels

Additionally removed dots from the end of each message, they seem
to be odd.
Merge branch 'master' of github.com:jtalks-org/jcommune