add control to prevent changing normal motion

[ghost]

I believe the a control should exist to prevent all of the code from 263 to 292 of .vimrc (all the WrapRelativeMotion code and the remap of j,k to gj,gk)

[lukedomanski]

done, see #464

I only put the option to disable remapping $, 0, ^, to g* versions, as the remapping of j and k was not part of @memotype's original change that I was fixing.

Awaiting confirm of other changes before sending pull request.