Replace brython_stdlib.js and brython.js in unittest by idividual javascripts files
Replace brython_stdlib.js and brython.js in unittest by idividual javascripts files

This makes it easier to debug as one does not need to rebuild the files
with every change.

brython-dev/brython,Hasimir/brython,jonathanverner/brython,Hasimir/brython,jonathanverner/brython,brython-dev/brython,brython-dev/brython,jonathanverner/brython,kikocorreoso/brython,Hasimir/brython,kikocorreoso/brython,kikocorreoso/brython,jonathanverner/brython,Hasimir/brython