support for different OS Users and different GemStone Users

[dalehenrich]

@marianopeck has a separate OS user and GemStone user (not DataCurator) for each of his stones.

Here are several checkpoints discussed in Buenos Aires:

• [ ] there's a sysadmin user that owns the scripts and shared code
• [ ] UMASK of 700 should be expected for each stone
• [ ] .topazini in each stone directory, read only includes hard-wired GemStone User and password
• [ ] OS_USER and HOME(?) env vars defined in stone.env
• [ ] startTopaz, startStone, stopTopaz, stopStone, createStone all:
  • cd to $HOME
  • use su if $OS_USER is not the same as $USER

The basic plan is to create a branch for this issue and start making changes (shared with @marianopeck) until we get things in good enough shape to merge into the master branch.

@marianopeck, could you chime in with anything I might have missed?