Let 'allocate' accept static memory that is defined as UTF-8 string with...

... character codepoints being the byte values

This is a small patch to the "allocate" function, which let's it accept a UTF-8 string, defining static memory. The Unicode character code points of that string are the byte values in the to-be-allocated memory. For performance reasons, the patch does not check for (non-Latin 1) code points being outside of the 0...255 range. 

In order to turn the static memory regions that are currently defined as integer arrays, I created a quick-and-dirty script, which needs to be run on the emscripten output: https://gist.github.com/anonymous/74196a36efbb4733a6f5

This pull request is now augmented with the changes to settings.js and emscripten.py, which help serializing static memory as UTF-8 string (see https://github.com/kripken/emscripten-fastcomp/pull/57).
This seems potentially slow, like it should be done outside the loops perhaps?

In general, we should benchmark this. It seems like utf8 will be slower to write into memory compared to an array. Perhaps faster to parse, which might offset that? If not, then it seems to make the value less clear.