Add Android Map to discovery

Create a map under discovery tab by using MapView.

Signed-off-by: TengChou Yang <threefure@gmail.com>
Three button Added to discover page

Added Bikestore, Famous Spot and ubike button to discover page.

Signed-off-by: TengChou Yang <threeufure@gmail.com>
Add Event Listener to Discover page

Signed-off-by: TengChou Yang <threefure@gmail.com>