Feature: immutable upload and more

[ptpt]

Features

• Immutable process and upload: do not modify images 0430c71 process_and_upload: import_path: support read-only file system #276
• The command process writes all metadata a single file (image description file) instead of multiple files 081e6f6 Feature Request: Use only 1 file to log the image status #269
• The command upload supports upload given a image folder and a image description file (for advanced usages)

Improvement

• Simplify internal image states (now an image has only 3 states processed, not_processed, failed) a859732
• Simplify command line UI (which introduces some breaking changes)
• Improve the processing performance -- less image EXIF reading/writing improvements to processing times #251
• Improve sequence processing a859732 Please run --interpolate_directions AFTER detecting duplicates #383 Better interpolate image directions: based on GPS data, not only at image locations #395
• More unit tests and integration tests 5263409 f1d488b
• Use the logging module to log messages/events 5263409 0.5.0 probably cosmetic - logging  #342
• Update/Improve README.md a728461
• Upgrade piexif==1.1.3 and exifread==2.3.2 to latest a728461 change python exif library #398

Breaking changes

UI changes

• Remove --import_path: Instead of process --import_path path/to/images, use process path/to/images
• Remove --advanced: Not needed
• Remove --rerun: always rerun (re-process) due to performance improvement and less states c388688

Other changes

• Remove command post_process: No need because all information are written in the description file 60ee647
• Remove command interpolate
• Remove command process_csv: Will add back as a geotag source
• Remove all extract_* commands: No need because all information are written in the description file

Other fixes:

• Fix missing GPS reference 60ee647
• RuntimeError: Failed to interpolate image on first video of sequence #433
• Mapillary_tools does repeated compression #437
• omit 0 lat,lon gps points #338