Specifiy Tracking namespace for g_Resources

Allow to use g_Resources and not needing to use the Tracking namespace
Improve launch files

Image and CameraInfo topics can be passed to learnsifts.launch and
tracking.launch using image and info arguments.
Fix getter/setter for PublishMode

-> Rename setPublisMode to setPublishMode
-> Add a getter
Friendlier print for tgCamera
Add a gitignore files

Ignore vim swap files, ply/sift files, tracking.ini and jpeg files generated by
learning. If necessary, ply/sift/jpeg and tracking.ini files can be force
pushed.
Fix publish everything setting

Publish if tracking is fair quality and tracker is set to publish everything
Add ostream operator for mat3
Publish PoseStamped instead of Pose
Set default build to RelWithDebInfo
Improve ouptut look for ModelEntry
Move enums to a separate header with inline ostream operator
Fix for compilation on 13.04
Merge pull request #4 from gergondet/topic/MinorImprovements

Topic/minor improvements