upload.pm: allow direct hex upload
TODO: update
refactor default config handling
duino: rename --dir -> --root
Command.pm: rename config() -> board_config()
build.pm: add support for using different hardware
build.pm: fix arduino root
Command.pm: -.-''
Command.pm: do not die if board config is not found
Changes: update
upload.pm: fix match
upload.pm: add --hardware option here too
v0.08

 - Support direct *.hex file upload
 - Rename --dir option to --root (incompatible change)
 - Support using different hardware types (e.g. not-officially-supported MCUs)
 - Do not die when a board config variable is not found (this caused "duino
   build" to fail on pretty much every Arduino except Leonardo/Micro)