use built-in LuaJIT profiler instead of lulip

The profiling is performed with the command `./reader -p` for a PDF document on non-reflowing mode with "Fit to content width" zoom mode.

Exciting news is that there is a good potential for optimizing as in blitbuffer blitting and getAutoBBox.
```
====== ./ffi/SDL2_0.lua ======
@@ 89 @@
      | 		else
      | 			-- timeout mode - use polling
      | 			while countdown > 0 and got_event == 0 do
   5% | 				got_event = SDL.SDL_PollEvent(event)
      | 				if got_event == 0 then
      | 					-- no event, wait 10 msecs before polling again
      | 					SDL.SDL_Delay(10)

====== ./ffi/blitbuffer.lua ======
@@ 418 @@
      | local BB_mt = {__index={}}
      | 
      | function BB_mt.__index:getRotation()
   4% | 	return rshift(band(MASK_ROTATED, self.config), SHIFT_ROTATED)
      | end
      | function BB_mt.__index:setRotation(rotation_mode)
      | 	self.config = bor(band(self.config, bxor(MASK_ROTATED, 0xFF)), lshift(rotation_mode, SHIFT_ROTATED))
@@ 499 @@
      | -- getPixelP (pointer) routines, working on physical coordinates
      | function BB_mt.__index:getPixelP(x, y)
      | 	--self:checkCoordinates(x, y)
  18% | 	return ffi.cast(self.data, ffi.cast(uint8pt, self.data) + self.pitch*y) + x
      | end
      | function BB4_mt.__index:getPixelP(x, y)
      | 	--self:checkCoordinates(x, y)
   5% | 	local p = self.data + self.pitch*y + rshift(x, 1)
      | 	if band(x, 1) == 0 then 
      | 		return ffi.cast(P_Color4U, p)
      | 	else
@@ 622 @@
      | 	for y = dest_y, dest_y+height-1 do
      | 		local o_x = offs_x
      | 		for x = dest_x, dest_x+width-1 do
  13% | 			setter(dest, x, y, self:getPixel(o_x, o_y), set_param)
      | 			o_x = o_x + 1
      | 		end
      | 		o_y = o_y + 1

====== frontend/document/document.lua ======
@@ 244 @@
      |     -- render
      |     local page = self._document:openPage(pageno)
      |     page:draw(dc, tile.bb, size.x, size.y, render_mode)
  14% |     page:close()
      |     Cache:insert(hash, tile)
      | 
      |     return tile

====== frontend/document/koptinterface.lua ======
@@ 141 @@
      |         --DEBUGBT()
      |         --DEBUG("getAutoBBox:native page size", native_size)
      |         page:getPagePix(kc)
  12% |         local x0, y0, x1, y1 = kc:getAutoBBox()
      |         local w, h = native_size.w, native_size.h
      |         if (x1 - x0)/w > 0.1 or (y1 - y0)/h > 0.1 then
      |             bbox.x0, bbox.y0, bbox.x1, bbox.y1 = x0, y0, x1, y1
```