Backported Debian changes applied upstream that provides app stream org.tigervnc.xtigervncviewer.metainfo.xml information for the TigerVNC viewer.

Correctly initialize XDG_SESSION_DESKTOP, XDG_CURRENT_DESKTOP, XDG_SESSION_TYPE, and XDG_SESSION_CLASS.

Provided example configuration for tigervnc-xorg-extension. However, this is still broken due to bug #855441.

- 2daf41 Fix typo in mirror monitor detection
- 1a729d Fix handling of VMware cursors
- 88e96d Fix session resize after mirroring on Linux vncviewer

Use of uninitialized value $usedDisplay in concatenation (.) or string at /usr/share/perl5/TigerVNC/Wrapper.pm line 353.
Use of uninitialized value $usedDisplay in concatenation (.) or string at /usr/share/perl5/TigerVNC/Wrapper.pm line 356

Fixed debian/control to split of tigervncpasswd from tigervnc-common into its own tigervnc-tools package.

Refreshed copyright years and bumped version of man pages. Small content tweak in tigervnc.conf.5x (rfbwait option no longer exists).