Changed behavior to cache trigger element position

added ScrollScene.updateTriggerElementPosition.
For now it calls functions direct. needs event…
updated docs to group methods
docs: fixed in-page menu bugs
docs: fixed all scroll/slide/hash related issues
added: scene shift event

a new event fires every time the scroll position of either start or end
of the scene change.
renamed ScrollScene.triggerOffset

New Name: ScrollScene.triggerPosition
feature: sort scenes by start position

Scenes are now always updated by the controller in order of their start
position.
This ensures that the lowermost scene will have precedence when
triggering multiple scenes (i.e. when scrolling down fast).
fixed some stuff concerning shift event

Added new parameter `reason`, indicating why the scene has shifted and
correcting the shift on parent resize
bugfix: remove pin with reset didn't work properly

The css prior to pinning wasn’t properly restored…
feature: scroll to html element

also updated some docs
changed scene event logic (start/end/enter/leave)

0 duration scenes will now never trigger an end event (as is expected)
The events take place after the progress update on leave and before
progress update on enter.
changed triggerElementPosition

doesn’t trigger an event when the scene is added to the controller
anymore…
changed default build command
feature: added method setClassToggle

and the respective removeClassToggle
Removed logging from minified version.
changed option validation

checkOptionsValidity is now called before the change event to supply
the real value.
Also now options are checked specifically.
removed /_conf/jsdoc.conf.json
updated to latest build
corrected version number
optimized: scene option getter/setter

Change is now only fired if the value actually changed.
Furthermore every value is converted to the correct type.