[Gpsbabel-code] MTK logger patch

[John D. <e4b...@ya...>]

Hello, 
I've created a single patch against current CVS with a few fixes for the 
MTK logger module.
Thanks to Lorezo, Sato and a few other for reporting and 
fixing the bugs.

The following changes are included:
 * NMEA command handler may read back result, ie. error/status handling
 * Timeout during log reading will do a few retries before 
   fatal() occurs. Please let me know if this help, 
   (especially PPC Mac seems to have problem with large log files)
 * Devices with 4Mbyte memory are handled, fix 2mbyte limit as failover only 
 * Erase will check and only enable log if previously enabled. 
 * Log reader will check and only enable log if previously enabled. 
   !! Let me know if these functions work as expected !!
 * Log bitmask/size changes are handled correct
 * Zero satellites in view issue' is handled
 * Code cleanups from Lorenzo, ...
 * ... 

Regards
Per B