Moved Ieee154Address and LqiRead to radio folders.

As mentioned in the todo of
http://docs.tinyos.net/tinywiki/index.php/BLIP_2.0_Platform_Support_Guide
I moved some radio specific code to the specific radio folders.
ReadLqi now in radio chips folder.

Rather than use a bunch of #defines that defeat the purpose of the
modularity of TinyOS I moved the appropriate Lqi code to the relevant
radio folder.
Created a simple interface for Blip.

Rather than wiring directly to the CC2420 driver, this interface layer
allows Blip to wire to something more generic.
Split Ieee154BareC into two files

The metadata interfaces that BLIP needs are now their own configuration
file, in case a radio driver wants to provide Ieee154BareC without
providing any of the metadata features (such as LPL or a PacketLink
layer). These should be logically separated anyway.

Added better Ieee154BareC header comment to describe why that component
exists.