Added shell `clear` before `add --patch` and `diff --cached`

Thanks to [this question on SO][1].

  [1]: http://stackoverflow.com/questions/7534184/git-alias-multiple-commands-and-parameters

dotfiles/git-universe/before.gitconfig

@@ -3,13 +3,13 @@
 [core]
     editor = vim
 [alias]
-  ap = add --patch
+  ap = !clear && git add --patch
   br = branch
   cm = commit
   cma = commit --amend
   co = checkout
   com = checkout master
-  dc = diff --cached
+  dc = !clear && git diff --cached
   gr = log --graph --full-history --all --color --pretty=tformat:"%x1b[31m%h%x09%x1b[32m%d%x1b[0m%x20%s%x1b[0m"
   rb = rebase
   rbi = rebase --interactive