[Vimprobable-users] NavigationBack / NavigationForward are incorrectly reversed

[Matt C. <je...@gm...>]

Easily fixed by changing the default in keymap.h prior to building,
but GDK_o and GDK_i are incorrectly mapped if you are looking to keep
consistent with Vimperator/Pentadactyl firefox add ons, or with
VI/VIM.

^o should be NavigationBack while ^i should go foward.