Fix Travis CI for Noetic

[rhaschke]

This PR comprises several minor fixes to get Travis CI passing again. Some of them are preliminary workarounds for open issues:

• We don't yet have an official ROS Noetic docker image
• Use magic $(MAKE) variable to suppress build warning python_qt_binding#91: silence make warning
• rhaschke/python_qt_binding@4eedad5: silence (external source) warnings in sip build

[rhaschke]

Closing and reopening to retrigger CI.

[rhaschke]

@wjwwood, @sloretz: Do you have an idea why the ROS build farm reports a failure here?
The build job actually succeeds - we just have a few cmake and compiler warnings - but all of them are triggered by external sources.

I already filed an issue for the assimp cmake warning: assimp/assimp#3166
All the compiler issues are related to a new gcc/clang warning (-Wdeprecated-copy), which is triggered in the sip build, as this activates all warnings (-Wall) from Qt's cflags.
To suppress them, we would need a way to pass extra cflags to python_qt_bindings.
For the Travis, I use the following quick fix to do so: rhaschke/python_qt_binding@4eedad5
From my point of view, the correct solution to this issue is to declare all external includes as -isystem.

[wjwwood]

@wjwwood, @sloretz: Do you have an idea why the ROS build farm reports a failure here?
The build job actually succeeds - we just have a few cmake and compiler warnings - but all of them are triggered by external sources.

I don't think the Jenkins plugin that reports this stuff to GitHub distinguishes between unstable and failure, but I'm not 100% sure.

I already filed an issue for the assimp cmake warning: assimp/assimp#3166

FYI https://bugs.launchpad.net/ubuntu/+source/assimp/+bug/1869405 and ros2/rviz#524 and ros2/rviz#534

From my point of view, the correct solution to this issue is to declare all external includes as -isystem.

I would caution against this, as we've run into subtle issues in the past with include orders being messed up when using -isystem. I'd prefer to fix warnings where they are or use the pragma diagnostics to suppress warnings where we include them if possible. Patching python_qt_bindings also seems appropriate.