dtostrf update

Updated padding figure to allow code to be used at the other side of the
world
Corrected code and added updated GPS start string

Discovered that i had coded badly and should have read TINYGPS.h file to
see if hdop was a valid function (sic?).  Changed back to previous
value.

Updated the GPS startup code.  Now that i've got my fletcher checksum
for the GPS working i was able to calculate the correct checksum
Fixed coding errors

Removed some stuff, added some stuff.  With thanks to
http://computer-programming-forum.com/47-c-language/f431276d99c8bf50.htm
and the UBlox data sheet for help with comeing up with the code.