[linear_path]/[spline_path]: check existence of array whenver we access it
Cleanup example patches
[ci] update .git-ci/iem-co submodule
report error-codes in hex (with zero-padding to 4 chars)
Fix debugGL error tracking - make errors trackable via Ctrl+click
CPPExtern::post() now uses logpost() internally
simplify error() and verbose()
fix typo: C++ booleans are lower case