[turba] API getContact Patch

[Chuck Hagenbuch]

Quoting mbydalek at mobilemini.com:

> I noticed there was no error checking in the getContact method, so I added
> some in to just return false if an invalid key was given.

I've added some similar checks; generally we return PEAR_Error objects in API
methods if they fail, so I did that. Thanks.

-chuck

-- 
"But she goes not abroad in search of monsters to destroy." - John 
Quincy Adams