improve roslaunch and support remote node execution

[bulwahn]

These pull request provides a commit from the pull request bulwahn#6 and some important commits from the kinetic branch.

[bulwahn]

I tested the following builds:

• Without ROS_USE_PYTHON3="yes", bitbake core-image-ros-world builds successful.
• With ROS_USE_PYTHON3="yes", bitbake roslaunch builds successful, but bitbake core-image-ros-world fails with build errors described in Some ROS packages fail on ROS_USE_PYTHON3 = "yes" #570, which already occurred before this pull request.

[rojkov]

Should we put Upstream-Status into this patch?

[bulwahn]

I was thinking about this as well; but then deferred the activity for a next pull request because I would need to understand the whole rationale of the patch, re-build without the patch, see the error message, understand the patch and look if it has been contributed somewhere. Nevertheless, it should be added and should be really added to meta-openembedded and meta-ros. I just did not do it here for this pull request yet.

[rojkov]

Are these exports really needed? I've just tried to build without them and everything seems to build ok. Probably a comment would be useful why they are here.

[bulwahn]

I will check this.

[bulwahn]

I rebased this pull request from January: I could address @rojkov's comments by dropping the python-pycrypto recipe that is now with python3 support in meta-python.

bitbake core-image-ros-world built succesfully on this build configuration:

Build Configuration:
BB_VERSION           = "1.37.0"
BUILD_SYS            = "x86_64-linux"
NATIVELSBSTRING      = "ubuntu-16.04"
TARGET_SYS           = "i586-oe-linux"
MACHINE              = "qemux86"
DISTRO               = "nodistro"
DISTRO_VERSION       = "nodistro.0"
TUNE_FEATURES        = "m32 i586"
TARGET_FPU           = ""
meta                 = "master:f9324af88a99eca28b160fa31aa4516fd397e44b"
meta-oe              
meta-python          
meta-multimedia      = "master:b56fc26fefff498b10236ea6486a5d5624f726cc"
meta-ros             = "bulwahn-python-paramiko:27e95fdd3535cc8917e139d554ab79908fc69947"

with ROS_USE_PYTHON3 = "no".

[bulwahn]

CI is green; so, I will merge this pull request now.