Build/install/misc fixes; Hershey fonts support


- Build fixes resolves bug marcan/openlase#7 and adds "make install" functionality

- Font engine olGetFont() framework allows for new font types
- Hershey fonts support via libhersheyfont, if that library is installed:
    http://www.whence.com/hershey-fonts
    https://github.com/kamalmostafa/hershey-fonts
    Note: the simplest Hershey font ("futural") traces considerably faster than the OpenLase built-in default font.

- new demo app 'spin-text' (works with default or Hershey fonts):
    https://www.youtube.com/watch?v=8y04_yhh-ZM