Fixed RosLaunchNodeDialog.

- Added missing function arguments.
Added RosLaunchFileGenerator.

- Added support for ROS launch file generation.
Changed package.xml generation style.

- PackageXmlFileGenerator now uses xml.elementree to generate files.
Added roslaunch function.

- Added function to call roslaunch.
Added output-attribute.

- Added 'output' attribute for node-tags in roslaunch files.
Added keep_open parameter to execute function.

- Added parameter keep_open to execute function. This keeps an external
project window open if the process exits. Should be for debug purpose
only.
Added ROS Environment dock widget.

- Added dock widget to display and change current ROS environment
variables (ROS_MASTER_URI, ROS_HOSTNAME, ...).
Added start function for ROS launch file item.

- Added start function and corresponding menu action for ROS launch file
item.
Added start ros launch node function in workspace controller.

- Added start ros launch node function in workspace controller.
Added content to ROS environment widget.

- Added content to ROS environment widget. ROS_HOSTNAME and
ROS_MASTER_URI can now be set from IDE.
HOSTNAME and MASTER_URI can now be edited.

- HOSTNAME and MASTER_URI can now be edited.
Removed debug code.

- Removed debug code.
Added function to get current ROS environment variables.

- Added function to get current ROS environment variables.
Added more eye candy! =)

- Added icons for several group items.
- PyFunctionEditor cursor color can now be changed from settings.