need minor change in two DB methods

[koralchapnik]

in the DB methods:

• mostHelpful(int n, ICallback<List> callback)

• getTopRated(LatLng l, double radius, int n, ICallback<List> callback)

if n is bigger than the number of locations or users, just return the existing users/locations without throwing an exception

[kapalex]

Note that this is already the behaviour for mostHelful users, just the getTopRated need to be fixed

[kapalex]

I just tested it out in the app for both locations and users and both work perfectly, returning the the amount of users\locs when n is bigger. (Only problem I ran into is a spinner not disappearing on top rated location) Note that I tested it on my phone with a version I put on it yesterday. Either way the bug doesn't seem to be with me.