Release 2020.1 PR's for review and merge

[taldcroft]

• Add kadi/events3.db3, remove eng_archive in favor of cheta_sync ska_sync#15 Add kadi/events3.db3, remove eng_archive in favor of cheta_sync
• Fix bash support on catalina + modernize ska_shell#15 Fix bash support on catalina + modernize
• Small fix for PCAD table generation + SCM version changes mica#213 Small fix for PCAD table generation + SCM version changes
• Utilities for getting and printing run time information ska_helpers#6 Utilities for getting and printing run time information
• Add ACIS raw-mode SI modes to ACIS states kadi#152 Add ACIS raw-mode SI modes to ACIS states
• Py3 server with + event/cmd cron jobs processing with django 3.0 kadi#143 Py3 server with + event/cmd cron jobs processing with django 3.0
• Add get_stars() function to get multiple ids / dates agasc#40 Add get_stars() function to get multiple ids / dates
• Changes to go along with the py3-server kadi branch find_attitude#7 Changes to go along with the py3-server kadi branch
• Add compile arg for building on MacOS Catalina / Xcode 11.2 chandra_time#34 Add compile arg for building on MacOS Catalina / Xcode 11.2
• Add --open-html option to open HTML in browser sparkles#130 Add --open-html option to open HTML in browser
• https://github.com/sot/Chandra.Maneuver/pull/14 Cast number of steps to int
• Initial steps to modernizing task_schedule task_schedule#15 Initial steps to modernizing task_schedule
• Modernize watch_cron_logs#6 Modernize
• SCM version #241 SCM version
• Update for kadi and scm also require core pkg updates for setuptools_scm 3.3.3 and django 3.0.1
• Update sherpa to 4.11.1 for OSX

Also considering

• Allow a fixed number of sync dirs instead of removing by date cheta#188
• Allow the timestep to be set from the model specification xija#48