avoid Key Error and issue warning if <app> cannot be inserted
raise and handle exception;
include measure info in warning
utility to get attribute values safely
display measure number and staff number in warning
replaced a debug message for better accuracy
more granular debugging in alt.py
fixed: not searching for mRest when adding rich wrapper
fixed: Index out of range when <staff> is empty
refined some debug logs
fixed: index out of range error at calculating effective time signature
fixed a syntax error in bulk massaging script
refactor and new utility functions
use safe attribute getter
remove redefinition of utility method
calculating duration of beams and chords as well
work in progress: linking rich elements with <annot>
'connecting apps' are defined under layer level
assert None at last measure
find connecting apps lower than layer level.
return transformed mdi from test runner to allow assertions