v0.4.0

Add the final piece: Google Maps

Features:

• Share location with friends (#22)
• Locate friend on the map (#23)
• Add 'find on map' button in friends' list (#24)
• Stop reading geolocation data when the map is not visible (#25)
• Add a search bar in the map (#26)

Bug fixes:

• Users disappearing from search after changing their names (#21)