Completes top level commands for now.

Signed-off-by: Pedro Melo <[email protected]>

 * skip any future options before the command;
 * if a command is matched, don't suggest anything else.

Signed-off-by: Pedro Melo <[email protected]>

 * move debug to a new _gh_trace(): enable with environment
   GH_TRACE_TO=/tmp/debug_file and tail -F $GH_TRACE_TO to watch it;
 * completion generation hidden away in _gh_comp(): for future reuse;
 * added util _gh_next_word() to figure out what is the next word in the
   command line skipping over options;
 * prepare for per-command completion rules.

Signed-off-by: Pedro Melo <[email protected]>

Completes users and branches.

Signed-off-by: Pedro Melo <[email protected]>

Only completes the known options, --ssh.

Signed-off-by: Pedro Melo <[email protected]>

Signed-off-by: Pedro Melo <[email protected]>

 * _gh_comp_opts accepts two lists, words and options. If the partial
   starts with a '-', completes with the options list. If not, uses the
   words list;
 * _gh_find_subcommand searches the command line for a valid subcommand.

Signed-off-by: Pedro Melo <[email protected]>

This could be improved, but works fine enough for now. See FIXME and TODOs
in the code.

Signed-off-by: Pedro Melo <[email protected]>

The command `gh network list` is used to obtain this list.

Still not perfect, see FIXME's

Signed-off-by: Pedro Melo <[email protected]>

Signed-off-by: Pedro Melo <[email protected]>

* 'master' of git://github.com/drnic/github-gem:
  added Dr Nic as one of authors

* 'master' of git://github.com/melo/github-gem:
  Added completion for 'pull'
  Make the `network web` subcommand complete with the full list of users
  Adds completion for the 'network' command
  Added utils _gh_comp_opts and _gh_find_subcommand:
  Added completion for 'create'
  Added completion for 'clone'
  Added 'browse' completion
  Code reorg:
  Improve top level command matching
  Initial version of a bash completion file for gh