Automatically fetching google version numbers.

Automatically fetching google version numbers.

Downloading maps from gogle requires a number embeded in the request uri.
These numbers are known to be changed by google over time.
Viking now tries to work out the current numbers instead of using the hardcoded.
This is done once right before the first google map download request, in a
viking session.

Signed-off-by: Quy Tonthat <qtonthat@gmail.com>