Merge branch 'master' of https://github.com/peterhm/gbd
BOOK: tweak spline plot
Merge branch 'master' of https://github.com/peterhm/gbd
Merge branch 'master' of https://github.com/peterhm/gbd
BOOK: update GBD hierarchy
Merge branch 'master' of https://github.com/peterhm/gbd
enh: removing graphic white space
book: graphics generator