Check for gps, network location enabled when app starts. about foursquared HOT 8 OPEN

There is already a check for the SD card in MainActivity.onCreate.

For location, if there is no location available, the NearbyVenuesActivity will 
come
up with a blank list.  I propose a code change so that we display a toast with
something like: "Your location could not be found, please refresh" and leave it 
up to
the user to refresh.  thoughts?

After looking at what happens if the SD card is not present, we need to change 
the
BaseDiskCache so it checks before trying to create the .nomedia file.

We'll handle the remaining edge cases for sdcards in separate bugs. We still 
need a 
good design for how to deal with users who have location providers disabled.

We now check at login.

I think it's fixed long time ago.