fix(disableRemote): send smaller message to stop showing ball
fix(disableRemote): notify about disabling only once

Previously, there was data stream to all clients (whose that needed to
enable and those who needed to disable showing balls).
Now to those clients that do not need to show ball, message is being
sent only once.
fix(notifyResize): update description of every client on resize

Previously, when one of clients resized the screen, other clients would
not know about it. Now, we update description on all clients.
chore(sharedWorkspace): add semicolon and make variable local
chore(workspaceManager): declare variables on top of methods
feat(maxDimensions): return object with maximum dimensions of workspace
chore(style): use mixin for width and height
fix(locking): fix locking mechanism

First who touch ball is now locking it, so other people cannot steal it.
fix(appendElement): dispose wams and readd it

This is made to fix #5. This is not proper solution to this problem,
but this is possible solution.
feat(minimap): add canvas and styles for it

Preparations for minimap