Merge pull request #528 from wolfmanjm/upstreamedge

add an additional offset to M306 if Z has a value other than 0
Merge pull request #529 from wolfmanjm/upstreamedge

fix M306 as per qharley (with improvements)
add md5sum for bootloader hex
Merge branch 'edge' of github.com:Smoothieware/Smoothieware into edge
allocate secind serial to AHBO
disable DFU by default
add dfu_enable to config
Merge pull request #530 from wolfmanjm/feature/disable-dfu-option

Feature/disable dfu option
add DISABLEMSD to options allowed on make command line