Added enum member documentation
Add transition doc: Command Arguments -> Commands
Compare only N characters of the string
Added Key parsing callback implementation

This callback handles the keys of the JSON object, the code was
previousely located in the string parser, that was wrong.

The code was also fixed by this move (variable rename from `str`
to `key`).
Do not allocate a new arg when starting parsing args

Each parsing step should allocate an own argument, it's less overhead
this way, as the final argument parsing step (the "hey, I'm ready with
the args" one) does not have to deallocate the last argument object.
Fix: direct/indirect was interchanged
Fix: We must modify the _last_, not the one before
Add documentation of direct/indirect arg state jumping
Introduced Arg direct/indirect states
Added implementation for indirect arguments

This adds the implementation of the yajl_number_cb() function callback
with code for a indirect value in the command argument array.
Add code for starting a new direct argument
Add value names
Added value type from name getter + stub
Add LEN() macro for getting array length
Add implementation of ws_value_type_from_value_name()
Add code for parsing the map key for direct argument values

This patch includes the new states.