CLI: add command to check compilation without emitting files

[folex]

In aqua-dht I don't need to emit .ts or .js files. But I want to have a command to make sure Aqua compiles.

Having a check command would be awesome. I'd use it as aqua check -i .

[alari]

Might be aqua -i ./aqua --dry or something like that, as it actually performs a dry run with a compiler backend of choice.

[folex]

In rust cargo check works way faster than cargo build cuz it doesn't need to emit anything, so can optimize.

That knowledge was why I asked for a separate command, just sharing it :)

[alari]

Yeah. I think now we can do --dry which is cheap, and optimize later :)

Now we don't have any commands for aqua, it works as a single command. This will change for sure, but I think it makes sense to add --dry earlier and then iterate on optimizations.

[folex]

Aqua Compiler 0.3.1-228

> aqua -i . --dry

aqua.js -m node_modules -i . --dry

Aqua JS: Missing expected flag --output!

Seems like I can't do --dry without specifying -o

And if I do specify -o, then it will be created even though it's --dry