Also get rid of some unnecessary global variables.

Makes sure we don't create the directories with root ownership.

Also make mwserv's stdout line buffered to work better with logging
systems which capture stdout.

(And less shouty.)

Wrap the userposn and struct person in a new user structure which can be
used to pass around all of the date related to the user, not just the
on-disk bits. This should make things easier down the line when
replacing the users.bb format with a more flexible one.

Now the client can use it too if necessary.

Move the bits which specified the default server options and config file
paths out of the config system. Add some bits to simplify constructing an
array of default config options.

Until now configuring mwserv has been limited to command line options
and build configuration. This config system should make things a bit
more flexible by adding the ability to load bits and pieces from a
json config file (or many json config files).

This is how it works:
1. A json object 'cfg' is built containing the build-time defaults for
   each config option recognised by mwserv. This will be used to
   validate the options in config files later.
2. A json config file in the user's home directory is loaded if it
   exists. It does not have to be complete: its contents will be merged
   into the defaults. Unrecognised options are ignored.
3. Otherwise, a config file in /etc is loaded and used similarly.
4. Command line options are parsed and the cfg object is updated with
   cfg_set_* in the order in which the options are found.
   4a. If the [--config|-c <file>] option is encountered, the file is
   loaded and merged into the cfg object as before.
5. Once all of the config information is gathered and merged into the
   cfg object, if the [--print-config|-P] option was given, the final
   merged config is printed in json format (mwserv then exits).
6. Config options are then accessed using the cfg_get_* type-specific
   functions.

This should allow the build system to be simplified in future, e.g.
'make test' could go away in favour of using ~/.mwserv.conf to store
the test environment configuration.

For now, the place to add new config options and their default values is
in cfg_init_defaults() in servercfg.c.

Tip: this can be avoided by adding this to your .vimrc:

match ErrorMsg '\s\+$'

Split out the who file stuff from files.* into who.* and tidy up the code a bit. Intention here is to modularise the who file code so that it can be replaced with a server-managed sqlite db (or whatever) easily in future. There's still a lot of code which does its own operations on the who file with read() and lseek() so a good next step will be to hide that code behind an iterator or similar.

Server will now exit if unable to open who list.
mw.spec now includes build dependency for postgresql-devel

Remove a bunch of unnecessary includes and remove --std=c99 from server/Makefile and webclient/Makefile since --std=gnu99 is already there.

server: Add some getopt boilerplate to accept options from the commandline and print usage. Currently only accepts --port and --help options.