Doing the seddery in Makefile breaks `npm run build`, webpack watching,
and was generally brittle.
Revert the sed/make rules, and instead do the font replacement hacking
with `string-replace-loader`, which fits into webpack much more nicely.
There is still some potential simplification by not duplicating the
entire scss loader chain.
This is deprecated API and will be dropped at some point, in favor
of projects shipping their own CSS.
Install and import the styles from PF4 now.
Update the travis config to run `make`, as `npm run build` by itself
doesn't generate the file.
Closes#315
