- replaced use of Object instance mutex with a private final Lock object
- replaced Object signaling with specific condition signalling

We don't need two separate executors for long-running IO threads.

Very important stuff.

- add a UnixRemovableDriveMonitor.checkEnabled to pre-emptively check if it's loaded
- os.arch is always x86,x86_64 on windows, i386,amd64 on linux
- source: http://www.java-gaming.org/index.php/topic,14110
- we'll deal with freebsd support when we come to it, jnotify doesn't even do this atm