None shall pass^Wleak

Well I think I finally got rid of all those memcheck warnings. \o/

Please bear in mind this is work in progress, any feedback is welcome.

What I did:
  * call cleanup functions for the lex scanners
  * freed all the variables that where malloced/realloced by the scanners
  * tried to do most of the cleanups in a functional way :)
  * There is a #define DBG_LEAKS in extsmaild.c if you want to trace things

===========================================================
$ valgrind --max-stackframe=6210928 ./extsmaild
==13101== Memcheck, a memory error detector
==13101== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==13101== Using Valgrind-3.9.0 and LibVEX; rerun with -h for copyright info
==13101== Command: ./extsmaild
==13101== 
==13101== 
==13101== HEAP SUMMARY:
==13101==     in use at exit: 0 bytes in 0 blocks
==13101==   total heap usage: 204 allocs, 204 frees, 88,345 bytes allocated
==13101== 
==13101== All heap blocks were freed -- no leaks are possible
==13101== 
==13101== For counts of detected and suppressed errors, rerun with: -v
==13101== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
===========================================================