Modify module methods in kamaki.cli classes

Refs: #9

Renamed to comply with pep8:
kamaki.cli.config.Config: _cloud_name --> cloud_name
kamaki.cli.shell: _init_shell --> init_shell

Merged with caller methods because they where used only once:
kamaki.cli: _construct_command_syntax, _num_of_matching_terms
kamaki.cli.utils: _parse_with_regex
kamaki.cli.one_cmd: _get_cmd_tree_from_spec, _get_best_match_from_cmd_tree