Update README.markdown

fixed typo (or perhaps changed syntax) for Surround quick help
Merge pull request #485 from aauthor/sd-typo_fix

Update README.markdown
Add vim-signify; remove vim-gitgutter

References #488.
add fullscreen mode for GVIM and Terminal
add bufferline, work well with airline
change airline theme, match with solarized theme
Merge pull request #498 from JoveYu/3.0

some useful configuration
Merge pull request #489 from mhinz/add-signify

Add vim-signify; remove vim-gitgutter
Merge branch '3.0' of https://github.com/spf13/spf13-vim into 3.0