Fixes bbatsov/prelude#528
Add operate-on-number

Replace prelude functions for increment and decrement of numbers.

Signed-off-by: Tu Do <tu.h.do@dektech.com.au>
Merge pull request #545 from tuhdo/master

Add operate-on-number
Merge pull request #532 from tatsuhirosatou/fixTrampRecentf

Fixes bbatsov/prelude#528
Merge remote-tracking branch 'bbatsov/master'

* bbatsov/master:
  Add operate-on-number
  Fixes bbatsov/prelude#528