Use proper device-specific theme for error dialogs
Add opencsv to project
Move loader.closeLogfile() to finally block to ensure it closes
Export feature now exports stuff!

Updated:

  - Use opencsv to export log entries to CSV file
  - First CSV line is a header describing each column/field
  - DatePicker listeners now update dates and filename
  - Misc clean-ups and improvements

To do:

  - Export between startDate and endDate instead of startDate and Today
  - Update progress dialog max to reflect above bullet-point
  - Save dialog states on device configuration changes (rotation)
  - Use string resources instead of hardcoded strings
  - More misc clean-ups and improvements