Merge pull request #41 from ericbmerritt/master

fix bug in override resolution
Check presence of each beam listed in .app

This allow to build riak, because one of riak deps (node_package) have stuff
in priv/ and valid node_package.app, but no one .beam files.
Merge pull request #42 from tsloughter/validate-app-file

Check presence of each beam listed in .app
keep application type of none for rel file
Merge pull request #43 from tsloughter/master

keep application type of none for rel file
back to travis for ci for now

Replacing README build status icon with travis until drone.io support PR builds.
do not write default empty sys.config or vm.args if it exists already
add lib_dirs option to for config file, same as -l cli arg
add -p for setting code paths
add rb16b01 and 02 and don't run dialyzer for r15 and below
fix deps target for shell target
add -v/--version cli option
create RELEASES file and include tarball so downgrade to initial release works
Merge pull request #44 from tsloughter/master

allow template for sys.config and vm.args add lib_dirs config option
Support upgrade and downgrade between versions

The "bin/RELNAME install" command now handles upgrading and downgrading.
It unpacks and installs new versions as needed, or just sets existing
releases as current/permanent as needed.

I renamed from "bin/RELNAME upgrade" because it handles downgrades too.
"upgrade" and "downgrade" are now synonyms for "install"

Additionally, when installing a new to-be-unpacked version, you can say:

  bin/RELNAME install 0.1.1/beat

OR just:

  bin/RELNAME install 0.1.1

in which case the /RELNAME part is added automatically. This is to keep
the version spec for downgrades the same as for new upgrades.

This is fully backwards compatible with the existing "upgrade" command.
Ensure exit codes propagate properly during upgrades
remove r16b01 and r16b02 from travis file since they don't exist in travis yet
Merge pull request #48 from erlware/create_RELEASES

run create_RELEASES on newly generated release
replace confusing disable-default-libs option with default-libs true or false
Merge pull request #49 from tsloughter/master

replace confusing disable-default-libs option with default-libs true or false