* introduce doctest over googletest #202
* call dtester in in targets
* doctest conversion #202
* channel.cpp -> doctest #202
* egcpool tests -> doctest #202
* input tests to doctester
* zaxis -> doctest
* drone: always define LANG
* libav to doctest #202
* panelreel tests to doctest #202
* spec that a C++17 compiler is now required for doctest #202
* enmetric tests -> doctest #202
* fade tests -> doctest #202
* notcurses test case -> doctest #202
* last conversion to doctest #202
* finish move to doctest #202
* drone: set up make test
* planereels tester #180
* suppress_banner in all tests
* tabletcb: start passing back tablet
* properly initialize fbbytes stat
* panelreel: logic fixes#178
* install all testing data
* put stdin into nonblocking mode, retry on short write to stdout #78
* wrap getc_blocking() around a poll #78
* get CCCflag from terminfo. stop clearing the screen in render/startup
* implement ncplane_at_cursor() #76
* ncplane_at_cursor() unit test for simples #76
* PlaneAtCursorComplex unit test #76
* PlaneAtCursorInsane() unit test #76
* nplane_at_cursor: return number of bytes, not just 0/-1
* uniblock-demo: add a bunch of pages from Unicode 12
* demo: make -d delay multiplier a float
* egcpool: check offset against poolsize in check_validity()
* notcurses_init(): set smkx/rmkx to NULL with pass_through_esc
* PlaneAtCursorAttrs unit test #76
* add ncplane_styles() accessor