Put in try-except so code works even if vpython module not present #13

	name: Python package

	on: [push]

	jobs:
	build:
	name : Python Package

	runs-on: ubuntu-latest
	strategy:
	matrix:
	python-version: [3.7, 3.8, 3.9, '3.10']

	steps:
	- uses: actions/checkout@v2
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v1
	with:
	python-version: ${{ matrix.python-version }}
	- name: Install dependencies
	run: \|
	export DEBIAN_FRONTEND=noninteractive
	sudo -E apt install -y cmake libgsl-dev g++ gcc git
	sudo -E apt install python3-tk python-tk
	sudo -E apt install -y libhdf5-dev doxygen
	python -m pip install numpy matplotlib vpython --user
	- name: Build
	run: \|
	python setup.py install

Provide feedback