rostest: rostest depends on rostest-native (resolves #83)

The rostest package requires that the rostest executable can be
found by cmake's find during configure. Hence, rostest depends on
rostest-native.
To implement this, rostest and rostest-native are defined with
different dependencies.

This commit resolves issue #83.
Merge pull request #97 from bulwahn/rostest-depends-on-rostest-native-v2

rostest: rostest depends on rostest-native (resolves #83)
catkin: adding runtime dependencies on python modules

The catkin_make command requires a number of python modules.
catkin: adding runtime dependencies on needed build tools

catkin is a build tool based on cmake and requires the common
build tools to work properly.
catkin: adding python-misc as runtime dependency

The catkin scripts require the ast python module, which is shipped
with python-misc.
Merge pull request #101 from bulwahn/catkin-runtime-dependencies

catkin runtime dependencies
catkin: adjustment for native recipe (cf. discussion #101)

The native catkin recipe has no runtime dependency on
the native version of packagegroup-core-buildessential.
Merge pull request #102 from bmwcarit/next

catkin: adjustment for native recipe (cf. discussion #101)
python-catkin-pkg: updated from 0.1.8 to 0.1.16 (see #99)

The current catkin requires catkin_pkg >= 0.1.12 as indicated in
https://github.com/ros/catkin/blob/groovy-devel/package.xml.
See discussion in #99.

lb: minor tweaking and commit message rewording

Signed-off-by: Víctor Mayoral Vilches <v.mayoralv@gmail.com>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>
README: acknowledge Victor Mayoral Vilches' contribution