1.0.8.6-alpha

Merged in changes from YABE svn repository:

• Avoid exception in Mstp thread with too small received packets (svn@199,200)
• Merge Properties with Date & Time into a single DateTime value (svn@196,204)
• Enums with new BACnet object types & properties (svn@193)
• New units form Addendum 135-2012ar (svn@192)
• Reject write at priority level 6 (svn@190)
• Bug removed with Andreas Becker's help (svn@184)

Other changes:

• Added LifeSafetyOperation to BacnetClient API
• Fixed decoding BacnetValue as DateTime/TimeStamp
• Fixed handling ObjectDisposedException when disposing BacnetClient