add handler property to yii\web\Session
simpler implementation of the handler property in yii\web\Session
Changed elasticsearch AR primary key handling

now supports mapped primary key when _id is part of source with an
alias.
timings fixed
Merge pull request #1781 from Ragazzo/profiling_panel_fix

timings fixed
added sorting links to debug toolbar

as requested in
https://github.com/yiisoft/yii2/pull/1781#issuecomment-31587963
https://github.com/yiisoft/yii2/issues/1478#issuecomment-31576474
fixes #1478
Do not unset class properties!

this will result in objects that do not have the property anymore :-)
try to fix basic app travis test.
docs added, guide style added.
formatting fix
early draft of api doc generator

issue #62
docs added
Merge pull request #1785 from Ragazzo/fixtures_controller_docs

Fixtures controller docs
fixed broken links in guide index

[ci skip]
fixed basic app build
renamed phpdoc extension to apidoc
simplified model and context creation
finished the model layer
removed unused log level from debug dropdown

the LogPanel already filters out profile so it does not make sense
adding it here.
run basic app functional tests within the main repo test chain