Bugfix: For f_file, use off_t, pre-test for EOF or error, use sizeof(f_char_t), and...

Bugfix: For f_file, use off_t, pre-test for EOF or error, use sizeof(f_char_t), and use size_t rather than ssize_t.

The fread() and similar stream functions actually use size_t rather than ssize_t.
Fix this bug by changing ssize_to to size_to for the affected functions.

Use off_t rather than f_array_length_t to be consistent with the types used in the libc/POSIX API.

Add additional checks for feof() and ferror() and the start of the stream read functions.
There needs to be a few more error codes, add a TODO comment to address this via a separate commit.

Use the size of f_char_t rather than 1 for reading.

Use >= in buffer read check rather than ==, just in case.