Added possibility to read TGraph from '.C' file (HEPData#135)

* added c_file_reader.py and test_cfilereader.py
* added notebook
* Fixed tests
* Add read_c_file.ipynb to README

Co-authored-by: Clemens Lange <clemens.lange@cern.ch>

.github/workflows/tests.yml

@@ -17,6 +17,7 @@ jobs:
             python -m pip install pytest_pylint configparser astroid pyyml papermill
             python -m pip install -e .
             python setup.py test
+            python -m pip install -e .
             python -m pylint hepdata_lib/*.py
             python -m pylint tests/*.py --rcfile=tests/pylintrc
 

README.md

@@ -57,6 +57,7 @@ There are a few more examples available that can directly be run using the [bind
 - [Reading in a CMS combine ntuple](examples/combine_limits.ipynb) [![Binder](https://mybinder.org/badge.svg)](https://mybinder.org/v2/gh/HEPData/hepdata_lib/master?filepath=examples/combine_limits.ipynb)
 - [Reading in ROOT histograms](examples/reading_histograms.ipynb) [![Binder](https://mybinder.org/badge.svg)](https://mybinder.org/v2/gh/HEPData/hepdata_lib/master?filepath=examples/reading_histograms.ipynb)
 - [Reading a correlation matrix](examples/correlation.ipynb) [![Binder](https://mybinder.org/badge.svg)](https://mybinder.org/v2/gh/HEPData/hepdata_lib/master?filepath=examples/correlation.ipynb)
+- [Reading TGraph and TGraphError from '.C' files](examples/read_c_file.ipynb) [![Binder](https://mybinder.org/badge.svg)](https://mybinder.org/v2/gh/HEPData/hepdata_lib/master?filepath=examples/read_c_file.ipynb)
 
 ## External dependencies