Goto & Labels
Goto-labels need to exist within their own, function-local scope
Disallow redefinitions of things in the same scope
parse_function would begin a new scope too soon
First cut on function prototypes - not really finished
Making function prototypes a bit smoother and misc tiny changes
add check if function label is redefined
Test cases for things
Merge pull request #32 from ojotoxy/master

Goto, scoping rules, function prototypes.