Do not display avatar on top of the connection problem messages

Previously the z-index was introduced in order to have the avatar
visible on top of the black video element, but now we're always hiding
the video element when the avatar is displayed, so it's no longer
required.

Make the stop recording dialog work again

feat(Mute_Participant): Implement warning dialog for muting remote participant

Change main toolbar animation; optimize mousemove handler

Page reloads on BOSH HTTP errors

Button shifted

Translations update

Adds a safe check, i18n is expecting undefined not null. Fix a method name and translation to be at placeholder.

The toolbar's mute buttons depict respective features/base/media states.
However, (un)muting is practically carried out by features/base/tracks.
When the mobile app enters a conference configured to invite the joining
participant to mute themselves, the tracks would be muted but the
toolbar's mute buttons would not reflect that.

error layout added

dropdown color changes

Relocate "HD" label

Reduce the z index of the connection problems message

Page reload overlay

For small window sizes and many video thumbnails the message may go on
top of the thumbnails.

Removing translateString forces using data-i18n attributes, to make sure we do not forget to set them. Missing data-i18n attributes is a problem with late loading where we can end up without translation, without text. Missing data-i18n attributes is also problem that strings will not be translated when changing language.
Fixes a bug in invite dialog, where remove password button was shown for non moderators.

Add JSDoc and rename method

Converts ConferenceUrl to a class and binds an instance to the global
APP variable, as requested by HTerezov.

Is not very readable and is not used across the project