fix #1033 Removing wrong lines in the MultiAutoComplete.

This commit removes two lines which set a new value in
the data model when pressing tab if the field is empty
and not positioned at the end of the options (i.e. when
leaving the edit mode through tab if the field is empty).

There is no reason to set the value at that time as the
value has not changed, and this can lead to the onchange
handler being called later when the value has not changed.
feat #1034 Disable method events by default

Backward-incompatible

This commit changes the default value of `this._enableMethodEvents` to
`false` in the `ModuleCtrl` class. The implications of this change are the
new default behaviors when calling any module's public method, as follows:

- no interceptors are added, the methods are called directly
- no events `methodCallBegin`, `methodCallEnd`, `methodCallback` are
  raised
- RefreshMgr is not automatically paused for the span of the call to
  the module controller's method

This commit should bring some performance gains.

In case the developer wants to continue having the old behaviors, he
should set `this._enableMethodEvents = false;` in the constructor of his
module controller, *before* calling the parent constructor.

This commit also removes the calls setting the mentioned variable to
false, since they're not needed anymore.

Close #1034.