Also indicate in the statusline if non-public tags are currently hidden.
Ctags seems to call an external 'sort' which can apparently fail in some cases with Cygwin. Since we sort the tags ourselves anyway just disable it.
Use psearch instead of pedit since pedit essentially reloads the file and creates an empty undo entry. This also makes it faster.
The current pause functionality simply removes all the autocommands to stop updating Tagbar. This has the problem that at the moment the statusline functions immediately restore the commands so pausing doesn't work, but even if that didn't happen it would stop the statusline functionality from working which is not desirable. The solution is to have a reference to the paused file which will get used by the Tagbar window, but not the statusline functions.
Plugins like MiniBufExplorer can trigger an update before window initialization has finished, leading to errors. Skip processing until that is done.