You can now toggle between autograb mode by pressing CTRL-ALT-G
 (default, can be adjusted in keystrokes.cfg).

 Fixes ArcticaProject/nx-libs#384.

nxagent does not react on that anyway (see xkb/xkbDflts.h)

These keystrokes where the same as their viewport_scroll variants and made
the latter being disabled.

Fixes ArcticaProject/nx-libs#770

The are now called reflecting their purpose:
viewport_scroll_left/up/right/down. This also regroups all the
keystrokes referring to viewport stuff.

Normal builds will not contain support for some keystrokes but warn
about unknown keystroke actions:

Info: ignoring unknown keystroke action 'debug_tree'.
Info: ignoring unknown keystroke action 'regions_on_screen'.
Info: ignoring unknown keystroke action 'test_input'.
Info: ignoring unknown keystroke action 'deactivate_input_devices_grab'.

So we remove those from the default keystrokes config.

Default is ctrl-alt-k

Both use the same keystroke 'f' (with different modifiers) for a very
similar function.

  Affected packagings scripts:

    debian/roll-tarballs.sh
    debian/rules
    nx-libs.spec

Use a keystrokes.cfg that reflects the normally hard-coded defaults of a vanilla nxagent. (Fixes: #223).