UI: remove unused shader components array
UI: add jg selection sphere to position tracker

Instead of mesh. Brings it inline w/ how this is done elsewhere
UI: disable depth write on ship & station indicators

These types of 2D artificats should not write to depth buffer
UI: force render during canvas entity reload operation

Hack needed to resolve a situation where certain components
weren't being reloaded properly due to three.js marking them
for removal after being added (instead of being added after
removed).

This call render during reload process so we're sure entities
are removed before readded
UI: add 'far' scene

Components indended to always be visible will be added to this
scene. Regular scene with be used for 'local' components and
have its clip plane reduced
UI: implement Canvas#reload_in_all to reload entity in all scenes
UI: add/remove component helper, add scene_components helper

Adds a few helpers to Omega.Canvas and Omega.EntityGfx.

The former extracts code from the add / remove entity methods &
adds appropriate calls to new methods. Also calls out to newly
added scene_components method which returns entity components
for given scene and can be overridden
UI: adjust skybox size

Independent skybox scene doesn't need to be as large
UI: set entity scene components appropriately

Cleans up track_cam module & renames set_mode to set_scene_mode
UI: update entities on scene mode changes not all cam changes

Fixes regression where incorrect variable is being checked
UI: remove far scene

Multiple scenes are useful in certain situations but this adds
too many complexities at this stage. May revisit in future
UI: correctly set ship/station indicator width/height
UI: update ship / station async gfx, small gfx tweaks

No longer include highlight by default, fix station indicator
loading
UI: use sprite for progress bar (ship hp, station construction)

Simplifies things greatly and looks nice