Added new option for cursor-blink property: scripted
Added dependency on lua.  Script is actually loaded.
Store Lua state in vte structure.

This includes ugly hack (forward declaration) to fight wierd "vte.h not
found" error
`render` function is actually called (no Canvas yet)
Render should work, but just causes segfault.
`render` draws something!
Fixed rectangle drawing, looks much better now!
Now need to explicitly call `fill`
"Breathing" effect draft