Bring across the base SpeedLines files from SPP.
Update the Color.h/cpp files with GRAY used by SpeedLines.
Update visual studio projects with SpeedLines files.
Update the Linux makefile too... just because I can :P
Integrated the speedlines.
Added a translation, added a settings entry and added a new string.
Merge branch 'master' of https://github.com/pioneerspacesim/pioneer into SpeedLines
Merge remote-tracking branch 'fluffyfreak/SpeedLines' into speed-lines
silence ordering warnings
always do lines in grey. don't show when going too slowly or too close to a planet or station
auto-commit: translation updates
always create a SpeedLines object and use the current config value to decide if we should use it or not
speed lines off by default
Merge branch 'speed-lines'
auto-commit: translation updates
auto-commit: translation updates
fix attempted double-translation ;) (thanks @shadmar)
run optipng on all PNG files to optimise and fix libPNG warnings

Recent versions of libpng (since 1.6 I think?) print a warning to
stderr when loading most of our PNGs. The warning is:

libpng warning: iCCP: known incorrect sRGB profile

and for some PNGs:

libpng warning: Interlace handling should be turned on when using
png_read_image.

This commit runs optipng on all our PNG files with this command:

  optipng -o2 -nc -nb -i 0 -strip all $IMAGE

Which strips the profile data from the image and rewrites it.
This fixes all the warnings, at the cost of generating a huge
commit and touching all our files.