build: allow user to build with dev/debug profile
build: allow user to build with dev/debug profile

The user can now invoke builds like the following:

    $ make DEBUG=true EXAMPLE_NAME=blink

This will build artifacts with the dev profile that includes
debug symbols and eliminates optimization that would normally be
included.  This is necessary to get a reasonable debugging experience
in many cases.

A few options were also modified in order to allow for the user
to override them if desired.

tempbottle/zinc,tempbottle/zinc,troplin/zinc,mcoffin/zinc,ntwyman/zinc,placrosse/zinc,phil-opp/zinc,hackndev/zinc,mcoffin/zinc,dirvine/zinc,troplin/zinc,tempbottle/zinc,ntwyman/zinc,ryankurte/zinc,tempbottle/zinc,richo/zinc,phil-opp/zinc,ntwyman/zinc,troplin/zinc,richo/zinc,posborne/zinc,hackndev/zinc,farcaller/zinc,dirvine/zinc,farcaller/zinc,phil-opp/zinc,placrosse/zinc,ryankurte/zinc,placrosse/zinc,hackndev/zinc,mcoffin/zinc,phil-opp/zinc,placrosse/zinc,ryankurte/zinc,posborne/zinc,richo/zinc,richo/zinc,hackndev/zinc,ntwyman/zinc,ryankurte/zinc,placrosse/zinc,ryankurte/zinc,farcaller/zinc,posborne/zinc,farcaller/zinc,mcoffin/zinc,ntwyman/zinc,dirvine/zinc,posborne/zinc,troplin/zinc,posborne/zinc,troplin/zinc,phil-opp/zinc,dirvine/zinc,dirvine/zinc,tempbottle/zinc,hackndev/zinc,mcoffin/zinc,farcaller/zinc,richo/zinc