Update vimrc: add vim-preview plugin
Update vimrc: fix <leader>ev mapping
Update vimrc: add <leader>o mapping (opens current file in chrome)

I added a mapping which opens the current file in chrome. You can easily
change this to whatever browser you use by changing the 'google-chrome'
section of the mapping to the terminal command to open your browser of
choice.
Update vimrc: remove vim-preview plugin
Merge branch 'pluginTesting'