Move main() out of radsecproxy.c.
Build a static library and link a main.c with it.

Also, change `test' to '['.

Not all systems have bash (esp. not in /bin) and some people argue
that /bin/sh should be less unsafe due to less code, lower complexity
and being around for longer time.

Fixes:
- /bin/sh builtin echo doesn't have `-e' -- use /bin/echo
- /bin/sh builtin test ([) doesn't understand `==' -- use `='

Comment on VendorKeyHashed, from source:
We are hashing the first nine octets too for easier correlation
between vendor-key-hashed and fully-key-hashed log records.  This
opens up for a known plaintext attack on the key but the consequences
of that is considered outweighed by the convenience gained.

We produced 62 octets rather than 64.

(format_hash): Don't write past OUT_LEN.  Duh!

Also, log empty string if no Calling-Station-Id attribute is found.

(radsecproxy.conf.5.xml): Capitalize first letter of all references to
basic options.  This convention might help as a hint in block config
by showing when a basic option is being overridden.

Use capital initial letter for basic options, both in documentation
and example config.