Staging for Elemental-IRCd 6.6 release
Fix autotools build system
include/cache.h: Add support for bigmatix.
example conf: add tor blacklist
fix spelling typo (s/propegate/propagate/g)
./Config: Somewhat rewrote script, improved nicklen prompting and interrupt handling.
./Config: Remove unneeded code and handle ^D
atheme module: remove trailing whitespace
libratbox: Fix undefined behaviour advancing pointer beyond end of array.

The C standard does not allow constructing pointers beyond one past the end
of an array. Therefore, if size is an unsigned type (size_t), then
buf + size is never less than buf.

Clang on 32-bit took advantage of the undefined behaviour, causing
segfaults.

(cherry picked from commit fab79c5d25423884fc4f5e0a56d97cb59b618196)
Merge branch 'staging/elemental-6.6'
Elemental-IRCd 6.6