Weak Portal Plugin

At a glance high level indicator of portals in disrepair. Opacity is
used to denote how much it's hurting. (Bright means needs the most
attention.) Factors in current energy, missing shields, or missing
resonators. Red means it needs attention. Orange means the same thing,
except that it's down at least one resonator.

I realise this is in opposition to game convention where dim == almost
dead, but I tried it that way, and it just made no sense to me to do it
that way. The whole point is a high level way to quickly identify
portals that most need repairing. If opacity isn't done this way your
eyes are most drawn to the portals that least need your attention.
Description Added

Description added to plugins readme
Change Selected color back to red
Merge remote-tracking branch 'upstream/gh-pages' into weak-portal-plugin
Ditched orange, introduced dashes

Ditched orange as the indicator of missing resonator in favor of dashed
circle.

Corrected /plugin/Readme.md
Merge pull request #131 from vita10gy/weak-portal-plugin

Weak Portal Plugin