Semi working version w/o heading
Adds html charset
Gets rotation visible on canvas
Restores life sigils to screen
Fixes some rotation bugs
Changes keypress handlers.

Instead of using keymaster's key() method, use key.ispressed(), which
can check every frame which key is pressed rather than waiting for the
operating system's keyboard autorepeat to kick in. (Looking at you, OSX)

To compensate, tone down rotation and movement. (And note: later, add
a cooldown for bullet shooting.)