Fix bug in input.lua, make 0.9-ready, add utf8 editing

1) [input.lua] Pressing backspace while the cursor was at the beggining
   of the text removed the first character. Fixed thanks to riidom.
2) [LÖVE 0.9] Use setLine(Width|Style) instead of setLine. Split
   keyboard.pressed() into keyboard.pressed() and keyboard.textinput().
   (see readme)
3) [utf8.lua] Add support for UTF-8 text editing. May still fail
   spectacurlarly with invalid UTF-8 strings.

core.lua

@@ -99,7 +99,8 @@ local function draw()
 	for i = 1,draw_items.n do draw_items[i]() end
 
 	-- restore graphics state
-	love.graphics.setLine(lw, ls)
+	love.graphics.setLineWidth(lw)
+	love.graphics.setLineStyle(ls)
 	if f then love.graphics.setFont(f) end
 	love.graphics.setColor(c)