Added deluxe opacity setting for save button

[azsde]

Description

Allow deluxe users to set a custom opacity for the save button, and allow dynamic resizing of the button if wanted.

Opacity to 100% --> regular size Opacity to 0% --> 2x regular size

Motivation and Context

I wanted to improve the hide button feature, this allow a more customizable approach.

How Has This Been Tested?

I've tested on two devices running marshmallow and lastest xposed version.

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [X] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] I have added every class/field/method name to the Obfuscator class.
• [ ] My change requires a change to the documentation.
• [X] I have updated the documentation accordingly.

 Sidenote:

I've slightly changed the behavior of the save buttons so that they act the same for regular snap and for stories.

[marzika]

I have reviewer your changes, however I would not like to use an other library. Android is already capable of making a Seekbar preference.

Check here: https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/preference/SeekBarPreference.java

[azsde]

I'm going to check if I can rework the patch using your link.