Add MediaDataCollector and ImageDataCollector
Refactor data collecting and database classes to work with images
Add permission to read External Storage
Fix unit tests
Add image data demo view
Refactor MediaDataCollectors
Refactor MediaDataCollector
Add tests for MediaDataCollector
Implement file handling in ImageDataCollectorTest
Create sd card on the CI script
Add null checking for longs in DeviceData
Finalize ImageDataCollectorTest
Merge pull request #14 from TeamWhat/image-data-collection

Image data collection