Added extra parameters for mirroring the image

Added ROS dynamic reconfigure parameters to set IS_SET_ROP_MIRROR_LEFTRIGHT and IS_SET_ROP_MIRROR_UPDOWN.

I also changed the call to "parse_ini" to  a call to "parse" since, whatever way the camera calibration file was generated, you can convert the calibration file format from  INI to YAML and viceversa (see http://wiki.ros.org/camera_calibration_parsers). Expecting that a file that ends in .yml has its content in the INI format breaks other code that works with YAML files (e.g. the current implementation of MCPTAM).