Feature: Add additional network and socket related functions.

Feature: Add additional network and socket related functions.

Add the following:
- f_file_poll() for poll().
- f_socket_read_stream() for recv().
- f_socket_write_stream() for send().

Add f_poll_t, f_polls_t, and f_pollss_t typedefs.
This adds the appropriate array management functions.
To be consistent with type_file.h a new type_array_file.h is created to manage these.

Update the existing f_signal_read() to use the new typdef f_poll_t.

This includes unit tests as appropriate.