Config can be required or optional, not more
added comment what the CONFIGURATION const is
comments added
added missing ident member to ConfigurationMember
fixed comment
configuration member for last ary entry was not set
outsourced creation of new ConfigurationMember
Added lib: argtable 2.13

Added library argtable for command line argument parsing from

    argtable.sourceforge.net

As there is no git repository, I cannot include a submodule. So I
imported the .tar.gz file.

This branch is supposed for maintaining the lib argtable.
Merge branch 'lib-argtable' into config
First add of arguments logic

Argument parsing with argtable library.

Basic stuff for argument parsing is added by this commit.
fixed indention of arguments
squashed verbosity options

Verbosity should be set via

    verbosity = 1

in config file and

    --verbose=2

    or

    --verbose

on commandline. Therefor we don't need --more-verbose and --extreme-verbose!
added description for configs
Implemented argument parser almost completely

This commit implements the argument parser part almost completely. Some fixes are
still required, as I don't know what to do if the argtable lib fails.

- initialize the literals
- build the argtable array
- parse the commandline options
- print error messages if there were errors.
added file comment
Merge remote-tracking branch 'uber/config_arguments' into config_arguments

Conflicts:
	src/config/arguments.c

Conflict was solved with manual strategy "their".
added function prototypes for (still missing) argument functions
added body of shutdown function
added implementation for get_by_identifier() function
Whitespace fix + comment for function implementations section