Patcher: add ability to remove all wrappers (unclude all third-party wrappers)
And restore "unload" listener (d7790e39f02f16f04179f612227fff6738c6028d), testcase:
* open new window
* add wrapper after Private Tab
* disable Private Tab (unable to remove wrappers)
* close window (unfortunately garbage collector unable to cleanup links to global variables itself)
(part 5 for #46)