update podspec

Merge remote-tracking branch 'chargemap/master'

Merge pull request spromicky#41 from martin1612/master

Fix slider pan issue with iOS 13

update version

add defaults to `initWithCoder:`

Fix spromicky#27

Implement haptic feedback spromicky#26

Update version files.

Carthage support.

More accurate `stepWidth` calculation.

Update podfile.