Log Message:
Update to 20080727.
Changes since 20080430:
 * Fix uninitialized pointer causing access violation error in
   some situations.
 * Extend maximum allowed wait time for upgrade upload complete message to
   allow for actual time required to upload. 
 * New API for channel scan.
 * Add model detection and model helper functions.
 * Use RTP by default so network loss can be detected.
 * Add define to enable exporting functions when building a Windows DLL.
 * Report reception/network errors when using the
   hdhomerun_config save command.
 * Increase the minimum signal threshold to approx -83dBuV. 
 * Fix segfault in hdhomerun_config when a logged channel scan is run under
   64-bit Linux.