remove cleanStackLine

I'm not sure what the point of this was.
Testing locally, they all seem to work
without it.

Author: greggman

src/utils.js

@@ -135,14 +135,10 @@ export function collectObjects(state, type) {
   return list;
 }
 
-function cleanStackLine(line) {
-  return line.replace(/^\s*at\s+/, '');
-}
-
 export function getStackTrace() {
   const stack = (new Error()).stack;
   const lines = stack.split('\n');
   // Remove the first two entries, the error message and this function itself, or the webgl-memory itself.
-  const userLines = lines.slice(2).filter((l) => !l.includes('webgl-memory'));
-  return userLines.map((l) => cleanStackLine(l));
+  const userLines = lines.slice(2).filter((l) => !l.includes('webgl-memory.js'));
+  return userLines.join('\n');
 }