Add ifdefs for compatibility with Player < 3.1

The Stage plugin contains some features (graphics2d multiline,
etc.) that were added in Player 3.1.  This commit adds some
code to let the latest version of Stage compile against Player
3.0.2 and earlier.
Add camera interface support to the Player plugin

This commit adds camera interface support to the Player plugin,
based on code originally provided to the project by Kevin Barry.
Images from Stage camera models can now be accessed by Player
clients like "playercam"
updated Player plugin to publish data at the natural rate of each model insteas of a fixed 10Hz
formatting
fixed race condition that would cause a crash if ranger data was visualized before being generated
removed map2.cc from build
improving libstageplugin so it can run faster than real time
better support for speedup in Player
fixed issue #36 GPS localization error
Merge pull request #32 from jpgr87/camera

Camera interface for Player plugin
fixed Player blobfinder interface, per issue #21
Merge branch 'master' of github.com:rtv/Stage