Compiler warnings

Hi Team,
I've reenabled the compiler warnings with -Wall and -pedantic-errors, 
i've excluded the enum value not in handled switch, but still we have 
many warnings which we should strive do eliminate, especially in 
surface_impl there is a big mix of signed and unsigned values, not a 
sign of clear code, i've fixed up most of the warning in the rest of the 
code, if you encounter any warning while compiling "your" modules please 
correct them.