Added new modal component.

[Rojoss]

Added a new modal component.
It supports pretty much everything from the bootstrap modal.
I didn't add footer stuff as panels don't have them either and I'd have to create a seperate syntax for it probably for it to look nice.
If you want me to do that then I'll do that but I think it's fine like this.

You can see them in action here:
http://gameboxx.info/wiki/bootstrap/modal

I've also added a modal attribute to buttons to be able to open the modals similar to the collapse attribute.

[giterlizzi]

Good job!

[Rojoss]

Thnx for accepting the pr's.
Sorry for the format/indenting btw my IDE doesn't seem to like 2 space indenting and stuff.
I've set it to two spaces but it still uses 4 for some reason. :p

I've started on #33 btw.
You can see it in action on this page:
http://gameboxx.info/wiki/styling

If you have feedback on it please let me know.
Will create a PR later tonight probably.

You can see the changes so far here:
master...Rojoss:pr-styling

[Rojoss]

I've created a PR for it already. #34