Add customizeable command line

[Aciz]

Since the app allows you to specify the compiler used, it would make sense to allow passing custom compiler switches that might be supported by other compilers. For the switches layout it makes sense that it matches the switches of mapcompiler, but this basically allows no flexibility when it comes to using switches exclusive to other compilers.

[isRyven]

There are these switch groups like "common" and "debug", i was thinking of adding "custom" group as well, to allow inserting custom switches using add button, which then would display the switches in the same grid as other groups are, this way you can actually control the switches through toggle and text fields.