Initial staging for economics view improvements.
Added label indicating current system and selected system, also if there are no items in a trade category.
Colour adjustments
Merge branch 'master' of github.com:Dessimat0r/pioneer into econ-improv
It could probably use some optimization and I'm not sure about exact correctness of math used, but it should be immeasurably better than what we had before.
Planetary Temperature Fix for Multiple Stars

Temperature for planets in multiple systems should now be calculated correctly, or approximately correctly in all cases.
Fix for temperature overflows during system generation.

Everything normalized to Earth's values like a good little Earth chauvinist should.
Fixed temperature calculation for binary orbiting planets in quarternary systems.

Bug due to misinterpretation of (rare) orbital configuration, fixed by reordering of conditions checked.
Merge branch 'temperature_overflow_fix' into multiple_system_temperature_fix
Added (obvious) check to functions checking if body is coorbiting.
code by Dessimat0r brought back from the dead (issue #210)
initial
Fix too short char buffer to fit string in trade comparison analysis.

For two systems with long names, (E.g. Epsilon E. and Kapteyn's Star) the
string would get clipped.
added tooltips and new buttons
cleanup
comment code and rename variable
NewUI graphics for the cpanel
fix Lua error when an axis binding is cleared in the settings screen
make KeyBindings::AxisBinding fields private
add an explicit (non-blank) string representation for disabled KeyBindings

This is necessary because blank config entries are treated as missing,
which means that if you clear the binding for an action, then the next
time the game config is loaded, that binding will reset to its default.