Auto button bar / Skin.py patch

[Huevos]

This piece of code allows skinners to create a fully automatic button bar. Once the skin is updated it will automatically show the correct buttons based on what is assigned in the python code. The code is backwards compatible so all current skins will continue to work normally, but it is advisable to update your skins to this style of button bar as it will adapt automatically to changes in the python code.

Skins already adapted:

• Simple Ten Eighty
• ViX Day HD
• ViX Night HD
• iSkin Light
• iSkin Dark
• Magic HD
• Magic FHD
• YouViX Blue
• YouViX Green
• YouViX Red
• YouViX Purple
• ViXBMC 1080 Bello
• ViXBMC 1080 Confluence