Menu Functionality & Config File

* Changes to clickable script:

- Commented Update Section ( To be Uncommented if
Input.simulateMouseWithTouches doesn't allow touch to call mouse events
).

- When mouse is over avaible options will turn text color red.

- When mouse is no longer over the text will change color back to white.

* Changes to GameControl script:

- Changed Application.LoadLevelAdditive to make it load from selected
menu level.

- Commented Update Section as it wasn't doing anything.

* Changed intro object and object that holds current level text to
allow:

- Added Tag "Intro" to intro object

- Added Tag "LevelID" to current level object

- changed the name of current level object to levelID

* Created script Config to allow load of files:

-  Write basic config xml as start

- Function to load levels

* Created script LevelSelect to allow level selection on menu:

- Loads level names from Config.cs

- Added to change level select on arrow key input

* Made changes to config.cs and gamecontrol.cs to allow levels to be
loaded on the path specified on the config.xml, but it will only work
after the second time that it is ran if you change the default path.
(unity free limitation)