Revert "Undo some of my changes to rendertext.lua"

This reverts commit edd347eb55.

rendertext.lua

@@ -70,7 +70,7 @@ function sizeUtf8Text(x, width, face, text, kerning)
 		if pen_x < (width - x) then
 			local charcode = util.utf8charcode(uchar)
 			local glyph = getGlyph(face, charcode)
-			if kerning and prevcharcode then
+			if kerning and (prevcharcode ~= 0) then
 				pen_x = pen_x + face.ftface:getKerning(prevcharcode, charcode)
 			end
 			pen_x = pen_x + glyph.ax
@@ -99,12 +99,10 @@ function renderUtf8Text(buffer, x, y, face, text, kerning)
 		if pen_x < buffer_width then
 			local charcode = util.utf8charcode(uchar)
 			local glyph = getGlyph(face, charcode)
-			if kerning and prevcharcode then
+			if kerning and (prevcharcode ~= 0) then
 				pen_x = pen_x + face.ftface:getKerning(prevcharcode, charcode)
-				buffer:addblitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
-			else
-				buffer:blitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
 			end
+			buffer:addblitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
 			pen_x = pen_x + glyph.ax
 			prevcharcode = charcode
 		end -- if pen_x < buffer_width
@@ -125,12 +123,10 @@ function renderUtf8TextWidth(buffer, x, y, face, text, kerning, w)
 		if pen_x < w then
 			local charcode = util.utf8charcode(uchar)
 			local glyph = getGlyph(face, charcode)
-			if kerning and prevcharcode then
+			if kerning and (prevcharcode ~= 0) then
 				pen_x = pen_x + face.ftface:getKerning(prevcharcode, charcode)
-				buffer:addblitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
-			else
-				buffer:blitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
 			end
+			buffer:addblitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
 			pen_x = pen_x + glyph.ax
 			prevcharcode = charcode
 		else