Update simpleproject.scd

[prko]

SuperCollider returns an error when evaluating this document.
I changed it to resolve the problem.

The eason of error:

The location of the sound file "a11wlk01.wav" is as follows:
Platform.resourceDir +/+ "sounds" +/+ "a11wlk01.wav";

[prko]

I think it is better to change the 7th line:

from

var projectPath = "~/tmp/reacollider-%.RPP".format(Date.getDate.stamp).asAbsolutePath;

to

var projectPath = "~/reacollider-%.RPP".format(Date.getDate.stamp).asAbsolutePath;