On startup, the Geany main window doesn't have a GdkWindow yet
(probably because it is not yet mapped). This causes many
'gdkdrawable-win32.c:2013 drawable is not a pixmap or window'
warnings when resolving shortcuts on Windows.
Since we pass the SLR_NO_UI to the Windows API, we probably
don't need the parent hWnd reference at all.

Don't rebuild TagManager workspace tags when quitting

Don't prompt for reload from infobar when there are no unsaved changes

Changed wrong translation of identation

When editor_create_widget() is used on an editor with already existing
widget, don't reset the internal indentation settings of that editor.

Closes #189

Updating the workspace is useless as the application will be shut down,
and not doing it can save a lot of time (almost 50% speedup quitting an
instance with all Geany source from `src/` open).

Also warn about losing undo history when there are no changes.

3e089e4c accidentally switched from
`g_get_user_config_dir()` to `g_get_user_data_dir()` as the location
for the user's configuration directory.

Force disk check before save to prevent accidental overwriting

Add project prefs for line breaking column & multiline comment completion

Remove unused tag manager files

Before we used g_get_user_config_dir() but GLib changed the returned
location in newer versions, so use the Windows API directly
to get the old location, at least for now.
Also add utils_get_user_config_dir() wrapper.

Code is based almost completely on a patch from Matthew.

In portuguese, there is no "endentação", but "indentação".

Fix typo in README

Useful e.g. with Save All when the modified file is not the current tab.

Don't use `g_regex_get_compile_flags()` that is new in 2.26, but we
only depend on 2.20.

Closes #340.

Project line wrapping pref

Fix adding stash group and applying defaults.
Don't let Properties dialog override per-document line wrapping state.
Use "editor" for key group name.
Remove code already handled by stash group.