work around strange webkit issue

when a css rule assigning width: 100%, border&padding: 0 existed
for textareas, the editor would slow down to a crawl on webkit
for some unfathomable reason

Author: marijnh

lib/codemirror.js

@@ -25,7 +25,7 @@ var CodeMirror = (function() {
         '<div style="position: relative">' + // Moved around its parent to cover visible view
           '<div class="CodeMirror-gutter"><div class="CodeMirror-gutter-text"></div></div>' +
           '<div style="overflow: hidden; position: absolute; width: 0; left: 0">' + // Wraps and hides input textarea
-            '<textarea style="height: 1px; position: absolute;" wrap="off"></textarea></div>' +
+            '<textarea style="height: 1px; position: absolute; width: 1px;" wrap="off"></textarea></div>' +
           // Provides positioning relative to (visible) text origin
           '<div class="CodeMirror-lines"><div style="position: relative">' +
             '<pre class="CodeMirror-cursor">&#160;</pre>' + // Absolutely positioned blinky cursor