Add plugin Startify

Quite a good idea to use the start screen!
http://www.vim.org/scripts/script.php?script_id=4544
Minor updates from the original plugin for my taste
Add plugin PSearch

http://www.vim.org/scripts/script.php?script_id=4436
A plugin that can see the search result accumulately.
Not very useful but good for searching large file.
Since it is loaded quite fast, it won't hurt.
Updates