Fixed section addresses to actually put boot loader in boot space!

Didn't realise that the AVR used 16-bit instructions (what an
admission!) and byte-wise memory addressing. Consequently, I'd
but the boot loader in the middle of memory instead of the end of
memory. Consequently, the boot loader couldn't write/erase the
space that it was actually located in.

Three days well spent, me thinks...
Used generic page erase defines from boot.h.

As part of debugging, replaced specific __boot_page_erase_short()
calls with boot_page_erase calls. boot.h already has #ifdef's in
place to pull-in the correct code depending on the AVR architecture
used, so better off letting the tool chain decide for us, eh?
Added new board variant 'allegro' to boards.txt

Added 'allegro' board variant so that pins are mapped to the Arduino
Uno board layout. Also enabled verbosity when compiling - didn't seem
to do anything though.
Added ATmega32C1 LIN baud rate registers.

Added detection of the LINBRRL/H registers to allow inclusion of
Serial in sketch for Allegro board.
Removed dependence on LINBRRL.

Made #ifdef dependent soley on LINBRRH like for other MEGA MCUs.
Added ATmega32C1 as a 4 interrupt part.
Many changes to HardwareSerial to supprot LIN module in UART mode.

Too many changes to list. Basically building in the necessary changes
to use the mega32c1 LIN module in UART mode. About 1/3 done.