Scipion-em

Developers:
- execution mode moved to class level

Users:
- Fix: 'Volume' object has no attribute 'getCompatibilityDict' when using join sets with Volumes
Developers:
- SetOfData replaces SetOfStats for generic tabular data.

Users:
- Fix: CrossSubset protocol works with "id" or "_objId" field too.
- Fix: Edit set protocol works with complex sets (titlseries, Classes2d) but not editing subelements for now.
Developers:
- New constants for "id" and "_objId": ID_COLUMN='id', ID_ATTRIBUTE='_objId'
- ImageReadersRegistry closer to image handler. Reader (tif, Pil) have write method. Tests added.

Users:
- Chimera viewer compatible with newer versions (flatpak, deb, windows via WSL) via linking

Developers:
- Generate a stack of images or a volume from a list of PIL images using ScipionImageReader.

Users:
- Filehandlers for cs, star and sqlite files to be displayed in the Scipion metadataviewer.
- Generalizing the method for checking the match between files and objects identifiers
- New variable: SCIPION_EM_NEW_FILE_CHECK_SEC, default to 10: defined in the environment determines the number
of seconds to wait before checking if new files are available or finished in streamified import
protocols.
- Fix volume halfmaps wrong filename
- Join heterogeneous sets are possible for tomography objects TS and tomograms.
- Adapted to new changes in metadata-viewer (v.2.0)
- xmippLib missing message less critical for those domains without xmipp need.
- Displaying calculated columns from the transformation matrix
- Durations like timeouts in streaming can be specified as "1h 24m 36s"

- Hot-fix: SetOf3DClasses and other sets without visualization config can be shown in the metadataviewer