remove and ignore autom4te.cache/ in git
rename README.md in README for automake
use autotools magic to link pthread, pcre and rt

Instead of explicit linker LIBS in Makefile, autotools will find the
proper ones automatically.
fix propogation loop in lower precision archives

Loop index was wrong and carbond was sometimes reading more archive
headers then available in whisper files, hence occuring SIGFPE.
retry recvfrom() and accept() if errno is EINTR

This notably makes carbond usable with gdb debugger.