Update decompiler.py

Allow for python code to be  indented twice before the line of code starts.
Request help in correcting the syntax
Added screen support, fixed pickle newer versions

Sadly screen support doesn't parse back to the original screen language
now, but it is able to create python code which functions exactly the
same way. Tested it a few times and the code seems to work fine.
Merge pull request #4 from CensoredUsername/master

These change fix some problems related with unpickling the files and add support for the screen statement