#249 new virtual events <<NewLine>> and <<NewPage>>

[Jan Nijtmans]

TkCon and console.tcl need those virtual events to make sure that
<Return> and <KP_Enter> have the same binding without duplicating
it. And the entry, spinbox and text widgets can be simplyfied with
it as well.

<<NewLine>> joins <Return> with <KP_Enter>, while <<NewPage>>
does the same but then with the <Control> key.