Display dynamic text objects instead of baking text into assets

[stefanlesser]

This pull request removes text that was baked into assets and displays dynamic text objects instead. This will be helpful when translating the game into other languages.
I'm not proud of the repetitive code, and for sure this could be refactored into much leaner code, but I've never used PIXI before, and this does the trick. ;-)

Note: The Post_Post_Credits scene with the social buttons still uses text in assets. This is a bit trickier to change than it was in all other cases.

Some assets are also no longer necessary (in the Quote and Credits scenes), because removing the text made them empty, transparent images. I've still kept the images, and the references in the code to them. It would probably be good to remove the assets completely.

[stefanlesser]

Oh, and my work of editing the assets is pretty crappy, too… the preload background in particular. Sorry, only had Preview to do it.

[ncase]

Thank you again for doing all this! I'm currently finishing up my next interactive project (it's about alternative voting systems) but once I've finished it (by next week), I'll pull all this, and have a German version of WBWWB live somewhere! (As well as a new repo for others who want to help translate it) Many thanks again!

[terales]

@ncase can you announce new repository in this one or on your blog? I want to translate it into Russian.

[ncase]

@terales: I'll announce it here on this repo! (and also on my Twitter) Thank you!