Expose Pan gesture

Expose Pan Gesture.

Dup

1.1.7

another try at making this work

public var

1.1.6

making this a public var

Updating overlay background color

Making overlay background color customizable.

Updating to most recent master

1.1.3

moving this out to test

Updating to most recent master

1.1.4

Expose the API for evaluating the drawer height