Move functionality from riak_cli_manager into logical modules

This is a somewhat large refactor that moves the bulk of the code out of riak_cli_manager and into the following modules:

riak_cli.erl: User API
riak_cli_command: Action or Status command handling
riak_cli_config: Handle set and show commands utilizing cuttlefish
riak_cli_error: Centralize riak_cli error reporting
riak_cli_manager: Only become the ets tables owner for all modules by calling their init() functions.
riak_cli_nodes: Handle registering a node finder process and returning this to other code during normal operation. Also provide a safe_rpc/4 function.
riak_cli_parser: Functions to Parse and validate the command line.
riak_cli_usage: Handle usage registration and display

basho / clique