Some initial work on replacing icons with FA5

package.json

src/App.scss

src/components/emoji_input/emoji_input.js

src/components/emoji_input/emoji_input.vue

src/components/emoji_picker/emoji_picker.js

src/components/emoji_picker/emoji_picker.scss

src/components/emoji_picker/emoji_picker.vue

src/components/extra_buttons/extra_buttons.js

src/components/extra_buttons/extra_buttons.vue

src/components/favorite_button/favorite_button.js

src/components/favorite_button/favorite_button.vue

src/components/media_upload/media_upload.js

src/components/media_upload/media_upload.vue

src/components/nav_panel/nav_panel.js

src/components/nav_panel/nav_panel.vue

src/components/poll/poll_form.js

src/components/poll/poll_form.vue

src/components/post_status_form/post_status_form.js

src/components/post_status_form/post_status_form.vue

src/components/react_button/react_button.js