Rotate some mappings

`<CR>`     : [except in command and quickfix windows] go to Command mode, Vim `:`, currently `a`
`' <CR>`   : "Ex" mode, Vim `g Q`, currently `A`
`<S-CR>`   : "Ex" mode, Vim `g Q`, currently `A`
`<C-CR>`   : Vim `: !`, currently `' a`
`p`        : Vim `+`, currently `<CR>`
`P`        : Vim `-`, currently `<S-CR>`
`\``       : use given register, Vim `"`, currently `p`
`~`        : start/stop recording a macro, Vim `q`, currently `P`
`aa`       : join this line with the next, Vim 'J', currently `\`\``
`aA`       : join this line with the previous, currently `\`~`
`A`        : break the line, currently `~`
`<C-S-CR>` : UNDEFINE
Mappings for '+' and '-' instead of <C-E>, <C-Y>

`p` : scroll line down, Vim <C-Y>
`P` : scroll line up, Vim <C-E>

No more mappings for Vim `+` and `-`.
Treat <;> and <p> keys as opposite
Last Change: 2014-03-12