BF: fix variable name for Tcl install
WIP: disable travis-artifacts for the moment

It was breaking the build
BF+RF: fix syntax for else; default to clang
BF: install bz2; fix sudo, fix py prefix

The long haul continues
BF: add flags to suppress python clang error
BF: remove ill-advised bz2 configure step

bz2 does not have a configure step.
RF: patch system python for clang flags
RF: fix sys python patch; add png, bz2 link
RF: revert failing workaround for sudo
RF: debug / attempt fix of sys python patch
RF: add pkgconfig to ports install

ports install not finding freetype; try adding pkg-config
RF: remove debug print for sys python file
DEBUG: try removing bz2 flag for matplotlib build
RF: add pkg-config install for macpython
RF: try writing setup.cfg file

Trying to get mpl to find built libraries.
DEBUG: try removing -lpng from link flags
RF: use dynamic libraries for build
RF: delete bz2 pkgconfig as not needed
RF: add back full test matrix
RF: remove variables for bzip2 and pkg-config