Creating a catkin Package

cd ~/catkin_ws/src
#FORMAT
catkin_create_pkg <package_name> [depend1] [depend2] […]
#EXAMPLE
catkin_create_pkg MySigintHandler roscpp rospy std_msg

cd ~/catkin_ws
catkin_make

. ~/catkin_ws/devel/setup.bash

It will automatically create the package.xml and CMakeList.txt with the content it needs.

Package.xml

<package format="2">
...
  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msg</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_export_depend>std_msg</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>rospy</exec_depend>
  <exec_depend>std_msg</exec_depend>
...
</package>

CMakeList.txt

cmake_minimum_required(VERSION 2.8.3)
project(MySigintHandler)
find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msg
)
...