TODO
Basic gradle build for qpdf executable

Lots of problems: libqpdf is only the C++ files. There's also
libqpdf_c containing the C files. These need to be one thing. Also,
hard-coding paths to pcre and z libraries, no autoconf support, and
tons of other issuses. This is just very basic proof of concept.
Get rid of separate libqpdf_c
Add test driver. Ugly though.
options
Move lib declarations, installAll task
better installAll
commented alternative