added cache mset() base test
added phpdoc block for mset()
marked mset() test incomplete
Merge branch 'master' into cache-mset
moved common parts of db ActiveRelation and Query to traits

these parts can be reused in other ActiveRecord implementations
add relationClassName to AR to allow different relation classes

... for different dbms
fixed conflicting property declaration
Revert "added FileMailer implementation of mailer interface"

This reverts commit 7d6d01b4bc9d7a23a7f5ec2a145b60f4898c80d6.
Implemented file transport for mails.
Added display of installed extension to debug panel.
Added parameters to fileTransportCallback.
typo fix.
Adjusted extension list.
moved markdown dependency to required.
Fixes #1075: separated empty switch and empty display for ListView and GridView.
typo fix.
hide summary when empty.
fixed crud to work with table that has no PK but AR defines one
Fixes #1169: anchor doesn't work when enablePrettyUrl is false.
Fixes #1170