- Fixed a bug in ConcurrentUtil.exportInProcess which intermittently caused the RMI server VM to terminate early.
- Modified JVMBuilder to handle properties mappings as Map<String, String> instances rather than Properties instances (the latter is a legacy API with an improper generic signature, and its support for a secondary "default" Properties instance is very hard to support fully in this context). This led to a backwards-incompatible removal of some constructors, since the types for properties and environments are identical; the alternative would have been confusing. Also improved support for default backing Properties objects when they're provided -- defaults that aren't overridden are copied into the internal Map<String, String>.
- Added JVMBuilder methods to set individual properties/environment variables and to provide "defaults" -- alternatives to use if the key is not already in use.
- "Fixed" a bug in ConcurrentUtil.work which was leading to test failures. The "work" to be performed seemed to have been optimized away, leading to different behavior than expected (somehow, an interrupt was never detected.) I made some arbitrary code changes in the hope that optimization would be less likely, and that seems to have handled the problem, but no guarantees that it won't crop up again.
