added more meaningful package description

Author: fmauch

package.xml

@@ -2,7 +2,7 @@
 <package format="2">
   <name>catmux</name>
   <version>0.0.0</version>
-  <description>The catmux package</description>
+  <description>Catmux: Catkin and Tmux. Catmux is a ROS package to enable the user to start a tmux session with multiple launch files and scripts with ease.</description>
 
   <!-- One maintainer tag required, multiple allowed, one person per tag -->
   <!-- Example:  -->