Updated annotations schema and made a special client-only collection.

A special client-only collection LocalAnnotations mirrors Annotations
collection, but allows adding temporary client-only annotations. We use
this to be able to add temporary annotations for a current user which
are not stored on the server until user inserts some real data. Then we
upgrade a client-only annotation to a real annotation.
Added annotations control.
Cleared style for controls.
Added metadata to highlights.
Annotations control.
Explain git submodules errors better.
Added our medium-editor Meteor package (not one found on Atmosphere).
Fix our medium-editor package and activate it.
Added annotations meta menu.
Lock scrolling of only annotations and do not propagate scrolling to the whole document.

Happens especially in Chrome when you scroll to the end of list of all
annotations.
Style.
Use correct z-index order for meta menu icons.
Moved meta menu icons to the right.

Maybe it really looks better this way. Additionally, some trickery would
be needed to have meta menu be correctly opening to the left, because
setting overflow to auto crops all the content inside of the
.annotations. So meta menu cannot really grow to the left by the
default. (You have to move left edge of .annotations to the left to make
space and then move it back with padding.)
Merge branch 'master' into new-annotations4
Implemented delete button for annotations.
Support direct linking to highlights ID.
Experiment with MediumEditor
Use outer dimensions of display wrapper for scroller.

We want to exactly show in the scroller what is visible in the available
viewport space.
Check permissions for annotations and highlights
Show only those annotations which have a corresponding highlight visible.