enhance shared volume default configuration

previously the following the shared volume default configuration details were hardcoded.
while default behavior is unchanged, the following details can be overridden:

  sharing of all user home directories as "Home Directory" can now be turned off.

  default shared volume default configuration parameters can now be configured.
fix missing default volume config parameter

adding default shared volume configuration details (should have been in prior branch
commit)
fixing syntax error in shared volume config
Merge pull request #10 from jonoterc/volume_defaults

enhance shared volume default configuration