Fix package dep for python2/3

[jccurtis]

This bumps the package.xml to format version 3 as is done here and documented here. This bump allows the python-numpy dependency to work in python2 (melodic and earlier) and python3 (noetic).

[jccurtis]

The build's seem to be failing because the ROS version targets are both EOL.

[jccurtis]

@gstavrinos is there interest in bumping this for python3 (noetic) support? These builds are failing because of the CI matrix, not the package.xml updates. Thoughts? I could update the matrix too, either here or in another PR. Thanks!

[gstavrinos]

Since there are packages that are based on ros-numpy, I think that it should be best to support it for noetic. I would appreciate it if you could update this PR with the corrections.

[jccurtis]

@gstavrinos hey there! This fell off my plate but I've updated the travis config with a new build matrix which I'll get working for kinetic|melodic|noetic

[jccurtis]

The new build matrix works well for kinetic|melodic however noetic has issues with rosdep and tf. I tried bumping this to geometry (which means more deps) but this didn't work either. I don't know why this is happening since geometry is clearly listed here.

tf is currently used for transforming translations/rotations to 4x4 matrices using the tf.transforms module which was abandoned in tf2 to reduce dependencies (see here). An alternative transformation library is transforms3d but this seems like overkill for these relatively simple conversions. Thus, I removed the tf imports and ported the necessary functions with some docs to the geometry module.

[gstavrinos]

Hmm, I think the best alternative would be to use tf2, but since there's stuff missing, I think we should have @eric-wieser 's opinion on this.