Merge pull request #56 from tsloughter/master

warn on bad app during discovery and erts in tar fix
Add autodownloading of rebar to makefile when it does not exist on system
Merge pull request #58 from jwilberding/make

Add autodownloading of rebar to makefile when it does not exist on syste...
Fixed REMSH var to be properly defined in generated runner bash script. Cleaned up instances of ERTS_DIR/bin to use BINDIR instead.
Merge pull request #60 from n-clark/runner

Fixed REMSH var to be properly defined in generated runner bash script
include relx header with include instead of include_lib