Fix setting the arguments for cppcheck

This way it doesn't include the CACHE stuff from cmake in the call
to cppcheck.
Refs #8940
Fix cppcheck errors in SCDPanelErrors.

Refs #8940
Fix duplicate branch cppcheck error in SaveHKL

Refs #8940
Reduce scope of variable in SplineSmoothing. Fixes cppcheck error.

Refs #8940
Reduce scope of variables in TobyFitYVector, fixes cppcheck issue.

Refs #8940
Remove unused variable in ScriptingWindow, fixing cppcheck issue.

Refs #8940
Remove suppressions no longer required by cppcheck 1.63

Refs #8940
Merge branch 'bugfix/8940_cppcheck-fixes' into develop