Folder .idea is no longer tracked
Merge pull request #4 from ampatalas/android

Create welcome screen
Fixed invalid layout used in MainActivity
add onClick to buttons in activity_main.xml
edit AndroidManifest.xml
add res/menu/menu_main.xml and res/layout/activity_how_to_get.xml
add AboutActivity.java, HowToGetActivity.java, OptionsActivity.java, SightseeingActivity.java