Refactor scratch language and let the user specify m2c flags

[dbalatoni13]

Will solve #1418. Decided to push my work so far, so we can discuss it as I work.

[dbalatoni13]

I have this problem that the scratch's language is only decided below, when it gets serialized, so for now I just passed the compiler's default language to the decompiler at scratch creation. Do you have an idea how we could determine the language beforehand?

[dbalatoni13]

Maybe instead of putting together the --target flag manually, we could do the same what we do with compilers, just pass through the one defined in the preset (or scratch when the user decompiles after creation).

[ethteck]

I think we should probably have default language for compilers* and then bite the bullet and dedicated field on the scratch...? if it makes the most sense. I try to avoid adding fields to Scratch, but maybe this one is actually worth it

* I know we currently have compiler.language but we seem to rarely override it from C, where it should most likely be C++ for any gc/wii compilers.

[dbalatoni13]

I'm like 80% done with the feature. Have to get it to work and then we can start testing. :)

[dbalatoni13]

We have some things that are all queried from the backend and filtered on the frontend like useCompilersForPlatform and some that are filtered on the backend. I'm adding a feature that gives you a dropdown to choose a decompiler (as there might be more in the future), for this I did the filtering for available ones based on the arch, type and language on the backend as I didn't see a point of having a list of all decompilers on the frontend, is this solution fine?

[dbalatoni13]

Have to remove TODO comments.
Bugs: options don't load if there is no decompiler available
TODOs:

• pass the flags to m2c
• fix decompiler tests
• formatting
• test decompiler flags in presets
• fix translation of knr
• hide decompiler section if there aren't any available
• test, test, test