Misc fixes to allow running from subdirectory rather than root (/)

packages/rocketchat-assets/server/assets.coffee

packages/rocketchat-lib/server/startup/settings.coffee

...s/rocketchat-livechat/app/client/stylesheets/fontello.css

...ges/rocketchat-mailer/client/views/mailerUnsubscribe.html

...ons-flextab/client/views/stylesheets/mentionsFlexTab.less

packages/rocketchat-sharedsecret/sharedsecret.coffee

packages/rocketchat-theme/assets/stylesheets/base.less

packages/rocketchat-theme/assets/stylesheets/fontello.css

.../rocketchat-theme/assets/stylesheets/utils/_octicons.less

packages/rocketchat-ui-master/master/error.html

packages/rocketchat-ui-master/master/logoLayout.html

packages/rocketchat-ui-master/master/main.html

packages/rocketchat-ui/lib/getAvatarUrlFromUsername.coffee

packages/rocketchat-ui/views/app/audioNotification.html

packages/rocketchat-ui/views/fxos.html

server/startup/avatar.coffee