#3 refactor msp430 information memory interfaces

[Peter A. Bigot]

The existing Msp430Flash component makes architectural assumptions about how the four sections will be used that are inconvenient. Need a new component that knows how to deal separately with unlocking, erasing, copying data into, and locking specific sections. Given that implementation, Constants can use it for operations on INFOA and lock the section, Settings can use it for INFOC/INFOD page swapping, and somebody else can make use of INFOB with RAM swapping and no lock.

[Peter A. Bigot]

Addressed in merged dmm/constants branch