Tests added from #1
Don't omit tokens that does not seem useful

Because they may be useful at some point, like in this example:

    f() ->
        F = fun() ->
                    ok
            end.

Previously, line 2 was tokenized as [F, (, ), ->] (including only absolute
tokens), but now it is tokenizes as [F, =, fun, (, ), ->]. The latter is better
because the 'end' line 4 will be able to find 'fun' this way.
Update README on helper.vim keys
Tests added from #1