gsm v2.2.1 release candidate

[lauramaxwell]

Overview

Worked through release checklist, and ready for review!

gsm v2.2.1

This patch release primarily addresses minor report updates bug fixes. Specifically:

• Reduce size of flags over time table by only displaying the most recent 12 periods
• Return an object of class function from GetStrFunctionIfNamespaced()
• Generalize all Flag_* functions to a single Flag() function
• Use log4r framework set up in v2.2.0 for stopif()/stopifnot() calls
• Add Subject Disposition field to Study Completion domain

Test Notes/Sample Code

Connected Issues

• Closes #XXX