Capitalized instance.Error

I accidentally overwrote the instance.error variable with the new error
function, so I renamed the function to Errror.

I also fixed a forgotten call to this function in the hook library.
Removed unecessary type conversion from the render library

These tonumber calls are not necessary because all of these functions
have built in type checks.
Fixed drawTexturedRectUV and split up drawText

Fixed drawTexturedRectUV
Split up drawText(font,x,y,text,align) into setFont(font) and
drawText(text,x,y)
Added getTextSize so that you can align your text properly.