[AboutBase] Remove use of native key bindings

[prl]

When bug #576 is fixed, it becomes possible to correctly implement page up/down on the UP/DOWN buttons without using native key bindings.

Doing so simplifies AboutBase.

[Peter Urbanec]

Fix Issue #577: [AboutBase] Remove use of native key bindings

Requires the fix of Bug #576 (commit 2e05b54) for correct operation of paging.

[AboutBase]

Remove setBindings() & restoreBindings() and the call to setBindings() to remove dependence on native key bindings.

Remove no longer used imports of enigma.eActionMap and enigma.eListbox.

Increase the priority of the self["actions"] ActionMap so that the "up" and "down" actions in the "DirectionActions" over-ride the native bindings for UP & DOWN.

Add "up" and "down" actions to self["actions"] and bind them to pageUp() and pageDown(), which after the fix of Bug #576 will page correctly.

Add pageUp() and pageDown() methods to implement paging via self["actions"].

→ <<cset 4ff959e97567>>

[Peter Urbanec]

Merged in prl/easy-ui-4/Fix-bug-577 (pull request #342)

Fix Issue #577: [AboutBase] Remove use of native key bindings

→ <<cset 5db7e763dc93>>