Handle trailing newline in pasted data
Handle trailing newline in pasted data

When pasting tilt angles, some spreadsheet programs append a newline
which was not handled and would cause the pasted angles to be treated as
invalid.

OpenChemistry/tomviz,mathturtle/tomviz,OpenChemistry/tomviz,mathturtle/tomviz,mathturtle/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz