Decompiler improvements

[Kneesnap]

• Lots of minor changes to make the decompiled code fully supported by GMS1. (GMS2 untested)
• Support && + || if statements.
• Fixed numerous bugs, including if (temp_var_1 - 1) and a break bug causing some code to be omitted from the decompilation.
• Improved return logic,

Before:
if (condition)
 return 1
else
 return 0

After:
return condition

• Added option for scripts to show progress bars.

[Kneesnap]

Alright, I think that's everything. I'm able to export a working project without issue, after next commit.

[colinator27]

Previously it just represented negative origin as very large positive numbers (>~2.14 billion) due to the nature of signed/unsigned integers. This obviously didn't lose any data, but it makes it harder to deal with. So that fixes it for the library and editor in one, though the editor didn't need to be touched at all.

[krzys-h]