fix uninitialized error on clang
gtdoc: allow parsing of function pointers
add some comments to interface callbacks
introduct and use gt_tool_is_toolbox()
add GtToolIterator class
gt -list
add option parser methods
add gt_tool_create_option_parser()
extend gt -list
fix memleaks
add output of subtool names
use prefix separator in format string
use correct tool name
fix double free
add copyright
get rid of angled brackets in tool one-liners
add support for man page output
add `-createman' output to gt tool
fix invalid reads
improve Lua documentation for manpage output