MozStumbler v0.18.0

• Add RTL support (@xsoh)
• General improvements to MapActivity (@tamcap)
• Making lint happy (@tamcap)
• Display map accuracy overlay (@tamcap)
• Fix OpenStreetMap project name. (@Firefishy)
• Added missing translations as comments (@Djfe)
• Update German translation (@Djfe)
• Update zh-TW strings (@petercpg)
• Update Nederlandse Spoorwegen on-train WiFi (@martiensch)
• Update bn-BD translation (@rabbihossain)
• Fix strings.xml typo (@tamcap)
• Fix Persian misspellings (@cpeterso)
• Update Spanish strings (@rodmoreno)
• Update French strings (Wifi always/disabled + sat) (@pl6025)
• Update German translation (@Djfe)