Add a Specifier for text alignment and cell image

Add a Specifier for text alignment
Add a Specifier for showing cell image
FEATURE: pass whole identifier instead of key only in IASKButtonSpecifier delegate callback method
BUGFIX: readded deprecated method callback for backwards compatibility
Remove xib files - mimic their behavior in code
Readme fix
Prevent selection of toggle and slider cells
Merge branch 'feature/button-action-identifier' of https://github.com/VilemKurz/InAppSettingsKit
Added log message for deprecated -settingsViewController:buttonTappedForKey: method
Updated Readme to reflect IASKButtonSpecifier delegate change
Merge remote-tracking branch 'upstream/master'
prefix all non-Apple specifiers with IASK (i.e. IASKCellImage and IASKTextAlignment) in the macro definition
Added alignment property for TextFields, TitleValues, MultiValues; added highlightedImage support; bug fixes

Added alignment and image support in Readme;
added many new combinations for alignment & images to the sample app;
set better alignment defaults depending on the element type;
Added IASKAdjustsFontSizeToFitWidth; fixed leaks, simplified code
Fixed #4: PSMultiValueSpecifier causes popover on iPad to grow

thx @MartinBarron
Fix over-released assign properties.
Merge pull request #165 from nschum/fix

Fix over-released assign properties
Declare IASKSettingsDelegate as an IBOutlet

easier to integrate when loaded from a NIB
Sample app: Fix dynamic cell hiding and delegate setup, fix iPad popover demo
Fixed dynamic cell hiding for ChildPanes

fixed #167, thanks @diorcety
Added note in Readme about hiding a group of cells

As noted by @GeorgeMcMullen in issue #172.