add html5, js, css3 ... plugins.
reference from @Aminzai.
disabled plugin of 'SrcExpl'.
rename 'bundle-list.vim' to 'plugin-list.vim' for quick auto-completion.
add <F5>, <F6> to Preview current HTML file and <F7>, <F8> to toggle Menu bar.
disabled Menu bar.
Merge branch 'master' into testing/neobundle.vim