Lestrix 0.2.2

The native edition now runs on SDL2 and OpenGL (with OpenGL ES 3 and ES 2 fallbacks for Raspberry Pi and Mali boards) instead of GTK4, with a much faster terminal engine: scrollback stored in compressed segments, bulk text parsing on worker threads, reader and writer I/O threads, and an idle window that draws almost nothing. New: a paste button, a performance bar with hover help for every figure, lxcat (a fast cat for local tabs), a remembered sidebar state, and an installer that is a dialog program from start to finish (./install.sh: the choices, the sudo password, and the build and test output all appear in dialog boxes) that installs or removes Lestrix and can set it as the default terminal. The old Python/Qt prototype is removed from the repository (it is still in the git history), so Lestrix is Linux only for now. native/test.sh runs every test and native/benchmark compares Lestrix with the other terminals installed on your machine. Install: ./install.sh.