Web Preferences - Clarify requirements and ranges

[JacobKlein]

Web Preference changes needed:

- Some preferences should not be required
   -> "Switch between tasks every x minutes" (0 or blank could reset to 60)
   -> "Disk: leave free at least x GB"

- Required fields should indicate that they are required:
   -> "'In use' means mouse/keyboard activity in last x minutes"

- Fields with ranges should indicate the valid ranges (Percentages do not need to):
   -> "'In use' means mouse/keyboard activity in last x minutes"
   -> "Suspend work if no mouse/keyboard activity in last x minutes"
   -> "Switch between tasks every x minutes"
   -> "On multiprocessors, use at most x processors"
   -> "Disk: use at most x GB"
   -> "Disk: leave free at least x GB"
   -> "Tasks checkpoint to disk at most every x seconds"
   -> "Computer is connected to the Internet about every x days"
   -> "Maintain enough work for an additional x days"
   -> "Maximum download rate: x Kbytes/sec"
   -> "Maximum upload rate: x Kbytes/sec"
   -> "Transfer at most x Mbytes every y days"

- Some preferences need moved around
   -> "Leave tasks in memory while suspended?" should be in the "Disk and memory usage" section