* Do not shell-quote strings in the metadata token expansion function
  * This fixes https://github.com/xiph/ezstream/issues/6
* Expand all tokens at the same time in a way that ensures metadata
  is not additional input to expansion
* Simplify several functions and remove unused functionality

Fixed the copypasta mistake of using the PLACEHOLDER_ARTIST value in the PLACEHOLDER_ALBUM conditional.

This was a regression introduced by the cfg refactor

... and don't initialize global values twice while here

* Stop supporting systems without stat(2) while here
* Remove some additional configure checks for ubiquitous functions (>=C99)

* Move -m and -n command line options into the config file
* Restructure configuration file:
  - Group into "server", "stream", "media", "metadata", "decoders", and
    "encoders"
  - Untangle decoder and encoder:
    o Decoders match on file extensions and convert to a canonical "internal"
      format
    o Encoders create one of the supported stream formats, potentially using
      different parameters (like bitrate)
  - Consistently specify stream format
  - Enable reencoding by selecting an encoder
* Architecturally separate configuration file storage from parsing
  - Allows for different configuration back-ends in the future, like
    YAML, SQL, REST API, ...
* Support roll-back in case of error on (re)load
* Anticipate HTTPS support

The libxalloc was reincarnated long ago in a separate utility library.
It did a good job help make ezstream have robust memory management years ago,
but now it's time to move on and get back to basics.

The replacement introduces reallocarray(), which is an overflow-checking
alternative to both malloc (NULL ptr) and realloc().

While here, declare some module-internal functions static.

This makes ezstream log via syslog and stderr. The "real-time status
line" remains unaffected.
While here, make the output more concise and consistent.

Uses syslog

Why yes, it /is/ KNF!

I do not plan to ever keep that up to date in case they move again.
If you need a copy of the GPL, use the Internet or read COPYING.

* update to latest strlc*(3) and strtonum(3) functions
* isolate local_basename()