Add import feature and code clean up

[ernesst]

Change log :

• improved sport selection
• missing appname substitution and removed unused images
• back to appname cwayne18, ux and translation improvements. update it.po
• Add features: Importing gpx files from other folder through the contenthub, renaming and changing activity
• bumping the revision of the sotfware to 0.12
• Add GPX info feature next to editing
• Add refresh indicator to load gpx information + some cleanup
• created proper components to handle useful dialogs
• Code cleanup : Remove metrics, contentPickerDialog & Polyline
• fixed PositionSource not being closed and code claning
• Theme suppor