add visual edit for bitrate on Radio interface

[alexrayne]

Radio interface now provide visual edit of global configuration for bitrate, powerup/dn_time

• new visual elements are depends on configXML elements - if config of Radio interface provides elements with name : "bitrate", "powerup_time", "powerdn_time", editor for double value this settings are provided.

• assignment for that configXML elements is global - updates all motes interfaces Radio.