Define SP_PARITY_* more logically.
Use a more logical set of SP_MODE_* flags.
Make sp_flush take an option for what to flush.
Add missing @param port entry to documentation.
Add sp_drain() function.
Add sp_start_break() and sp_end_break() functions.
Add sp_get_signals() function.
Add missing @param port entries to documentation.
Fix to sp_flush() on Unix.
Ignore linux_termios leftovers.
Fix the build on non-Linux platforms.
Add missing #include guards.
Minor cosmetics.
Temporarily disable USE_TERMIOX code (breaks the lib).

On some systems the use of the code enabled by USE_TERMIOX leads to a
non-working sp_open() which breaks all functionality provided by the lib.

Thus, temporarily disable that code until the details are investigated.

This has been tested with a serial port DMM and the OLS logic analyzer
on an x86 64bit Linux system with kernel version 3.11. The code compiles
fine but doesn't work at runtime. The configure output included:

checking for struct termios2... yes
checking for struct termiox... yes

The root cause for the problem is that the ioctl(fd, TCGETX, data) call in
get_flow() returns -1 ("Invalid argument"), which in turn lets sp_open()
return SP_ERR_FAIL.
Use common 3-digit package version number.
Fix memory leaks.
Check for termiox support at runtime.