add allow switching directly from left to right panel

Changed so that unloading of panels is delayed until the switch is done.

Used mainly for ipad where both left and right buttons can be visible
at the same time, when using ```JASidePanelMultipleActive```
added possibility to add pan gestures to left and right panel

Two new preoperties:
```
recognizesLeftViewPanGesture
recognizesLeftViewPanGesture
```
If set to ´´´YES´´´, it will allow the user to close the left or right
panel by pan gestures on the view. Can be useful if the panel is in
filling the entire screen so that the centerpanel cannot be "dragged"
added podspec
Fix center animation

Added `UIViewAnimationOptionBeginFromCurrentState` when animating
the center panel. This fixes glitchy behavior when there is a
`UIToolbar` in the centerpanel with a overridden
`layoutSubviews`. Without this option the buttons in the
`UIToolbar` would be jumping around before animating into place. It
probably fixes other components with overridden `layoutSubviews` as
well.
Merge branch 'animationfix'
fixed rightpanel overlapping leftpanel issue
Merge branch 'overlapfix'
Added possibility to respond to when the sidepanels move/pan
Merge branch 'pancallback'

Conflicts:
	JASidePanels/Source/JASidePanelController.m
Merge branch 'reekris-master'

* reekris-master:
  Added possibility to respond to when the sidepanels move/pan
  fixed rightpanel overlapping leftpanel issue
  Fix center animation
  added podspec
  added possibility to add pan gestures to left and right panel
  add allow switching directly from left to right panel