Save bytecode to file through CLI

[NotDSF]

This pull request adds support to save script bytecode through the CLI using the --binary option. This feature is very useful for developers who would like to parse luau bytecode using 3rd-party programs, as said in this feature request #151

[zeux]

Thanks for the PR! A few notes:

• It would be better to reuse the code for compileFile, as well as the command line argument. I would propose --compile=format where mode can be text or binary, with --compile being equivalent to --compile=text, and a CompileFormat enum argument to compileFile (see Analyze.cpp where we do something similar for reporting). This will make it possible for us to add a different format that supports bulk compilation, e.g. msgpack where we output multiple bytecode blobs, one per each input.
• We should output data to stdout still; this requires setting file mode for stdout to binary on Windows. That allows the user of the command line tools to redirect the output to the file of choice.
• Please don't use std::ofstream - we don't use file streams to avoid associated compile time and run time inefficiencies - and use C output facilities like fwrite
• Please use the code style that matches the style for this project, e.g. { must be on its own line.

[NotDSF]

Thanks for the PR! A few notes:

* It would be better to reuse the code for `compileFile`, as well as the command line argument. I would propose `--compile=format` where mode can be `text` or `binary`, with `--compile` being equivalent to `--compile=text`, and a CompileFormat enum argument to `compileFile` (see Analyze.cpp where we do something similar for reporting). This will make it possible for us to add a different format that supports bulk compilation, e.g. `msgpack` where we output multiple bytecode blobs, one per each input.

* We should output data to stdout still; this requires setting file mode for stdout to binary on Windows. That allows the user of the command line tools to redirect the output to the file of choice.

* Please don't use std::ofstream - we don't use file streams to avoid associated compile time and run time inefficiencies - and use C output facilities like `fwrite`

* Please use the code style that matches the style for this project, e.g. `{` must be on its own line.

I have fixed these issues. You can now use --compile=format instead.

[zeux]

Please don't close this PR. It's not necessary - you can update it without closing - and that results in needless notifications for people watching the repository.

[NotDSF]

Please don't close this PR. It's not necessary - you can update it without closing - and that results in needless notifications for people watching the repository.

Sorry about that 👍

[zeux]

This should use fwrite to stdout since the data is binary

[zeux]

Thanks! Left a few comments.

[zeux]

This would be simpler if we just have if (argc >= 2 && strncmp(argv[1], "--compile", strlen("--compile")) == 0), and inside the if we can compare the argv to determine the format. That way you get to reuse the rest of the code between two branches.

[zeux]

This needs something like _setmode(_fileno(stdout), O_BINARY); when _WIN32 is defined, see
https://stackoverflow.com/questions/23107609/is-there-way-to-set-stdout-to-binary-mode

[Kampfkarren]

luau too?

[zeux]

Thanks! I'll take care of .luau support in a separate change.