Update asconfig command

- add an 'info' command to show metadata.
- Replace InputSupplier with ByteSource and ByteSink
- remove Generator and ZipGenerator, have ZipPackager use ByteSource
- allow init to omit the release or snapshot repo or both. Make release and snapshot smart enough
  to skip deployment if no remote repository is configured (required for local-only testing)
- Output groupId in various places to make the output align closer with GAV coordinates
- number of small fixes, mostly NPE edge conditions with no release and/or snapshot repository
Fix bugs with allow-duplicate-installations-on-an-agent.

- Make sure that the config setting is respected everywhere.
- If less agents than requested installs are present and duplicate installation is allowed, install
  more than one instance of a service per agent.
Try multiple configuration files for airship config and maven settings file.

If no user specific file exists, try

* /usr/local/etc/airship/airshipconfig.properties
* /etc/airship/airshipconfig.properties

This allows global installation of airship configuration instead of
requiring a per-user setup.

For asconfig, if no user specific ~/.m2/settings.xml file exists, try

* /usr/local/etc/airship/maven-settings.xml
* /etc/airship/maven-settings.xml
Some minor changes

- sanity checking for missing settings.xml file
- change output format to be cut'n'paste to airship deploy command.
code review feedback
Pass environment-file setting from agent to deployed services.
groupon local deploy