main: move til_init() to start of main

Currently this was done rather late for vestigial pre-libtil reasons;
it used to be a local function for specifically "create rendering
threads" purpose.

But it's rather awkward now to see such an initializer called late
after myriad other til_* API is being used, and there's nothing
gauranteeing til_init() will continue to strictly create rendering
threads.

Nothing is actually changing in what til_init() does here, it's just a
cosmetic movement of the call site and s/librototiller/libtil/ in the
error message.

0 files changed, 0 insertions, 0 deletions