ILI9341 Performance Improvements

@Gordon I wasn't suggesting there are many, the interpreter seems extremely "fluent" - I have only come across 3 issues:

The first was when closure decided to insert a labeled statement when I used a break or return within a loop - I can't remember the exact code, but I wouldn't expect labels to be implemented in Espruino and if this does occur it is extremely easy to see within the error message.

The second was as described above - closure identifies that the final semi-colon in a function is superfluous and removes it - Espruino expects a semicolon after a do.. while (and possibly after for loop as @allObjects experienced). The following code is valid but breaks when using simple optimizations

function test(){
       var i=0;
       do{
             console.log(i++);
       }
       while (i < 10);
}
test();

The final problem was with brackets being removed by the minifier - the precedence of operators must be evaluated slightly differently by Espruino. This was probably the most difficult to debug because an error wasn't thrown (correct answer is 256 but returns 0 when minified because outer brackets are removed by minifier )

function swap16(val) {
        return ((val & 0xFF) << 8)  | ((val >> 8) & 0xFF) ;
}
console.log(swap16(1));

I hope this simplified code helps - although minor its the sort of thing that may put beginners off the platform and that would be a pity because it can be extremely enjoyable to work with.