Implemented global variables.

It's a really BIG commit because a few things has changed:
1) global variables, yay! No initializers (like var<int> foo=1024;)
though, but nonetheless - we finally have global variables, isn't this
beautiful itself? ;)
2) I've finally refactored the SSC file format, now it's a lot better.
3) for example (ad. the point above) - now there's no need to create any
additional header files because function headers'/variables' and types'
structures are now saved to the SSC file and restored when it's loaded.
4) also some of the bugs I discovered during writing the main feature of
this commit were fixed (I technically should divide it to one bug = one
commit, but most of them I found when many things in the internal
compiler structure had already changed so I'd have to download the old
repo, fix bugs in the old code and do many other things that would only
waste my time thus I have decided to do one big commit).