Will be updated after initial review.-checked having no arc.land.onto.default still assumes 'master'
-test all combinations of: none, arc-checked 'arc.land.onto.default' still overrides 'master'
-checked upstream branch (of feature branch) overrides 'master' and 'arc.land.onto.default, --onto, no upstream (failure), --remote, default 'origin' upstream, tracked upstream.'
-checked '--onto' overrides all
-checked origin is default for non-tracking branches
-checked the land onto branch's upstream remote is used instead of 'origin'
-checked '--remote' overrides 'origin' and the tracked upstream
-tested several crazy branch names including 'something/like/this' for both the upstream and tracking branches
-tested on linux and OS X
-rinse and repeat on Windows