Changes in version 0.1.0 (2022-11-14):
+ initial version

Changes in version 0.1.1 (2022-11-18):
+ first working version

Changes in version 0.1.2 (2022-11-28):
+ allow selecting of cell types

Changes in version 0.1.5 (2023-02-14):
+ small fixes to solve check issues

Changes in version 0.1.6 (2023-02-23):
+ public release of cytoviewer on GitHub
+ main functionality done

Changes in version 0.99.0 (2023-03-23):
+ code preparations for Bioconductor submission

Changes in version 0.99.1 (2023-04-12):
+ code adjustments after Bioconductor approval
+ included reactive image / mask reading

Changes in version 0.99.2 (2023-04-13):
+ image download fix

Changes in version 0.99.3 (2023-04-18):
+ add initial color control for cell-level

Changes in version 1.0.0 (2023-05-26):
+ version bump for bioconductor and biorxiv release

Changes in version 1.0.1 (2023-07-27): 
+ added validation messages and fixes for metadata overlay
+ added more tests and validation checks

Changes in version 1.1.2 (2023-10-09): 
+ vignette updates

Changes in version 1.1.3 (2023-10-19): 
+ enlarged default display area and changed default color settings
