File / port cconventions and use

[DSMan195276]

the stty shell command works, it is persistent.
everything works so far except way to see if more data is in buffer.
LOC(1) seems to just count up every time a character is read.

That's good news if that's the case with stty, that would save you the more complicated part.

The issue of seeing the number of characters pending to read and not blocking on the GET is unfixable though. To not block on the read you have to set the opened file to "non-blocking" mode, but you can't do that with QB64 (and QB64 can't do it with the regular std::fstream it normally uses to read files).

For getting the number of bytes ready to read, there's not exactly a standard way to do that but it can be done using the `FIONREAD` `ioctl()` call on the underlying file-descriptor. QB64 doesn't expose that to you though (and QB64 doesn't have it, it's buried in the std::fstream) so this isn't possible to do. `FIONREAD` isn't really the way to go anyway, it still doesn't _really_ guarantee you won't hang. Opening the file in non-blocking mode is the best way, then you don't need to know how many bytes are ready since all calls to `read()` will not hang and will tell you if there was nothing available.