Possible collision with another orca executable

[MFolschette]

When using Plotly-Orca with Ubuntu 18.04, and while following the installation instructions, I met a problem that is not mentioned in the help: There already exists another binary named orca that is pre-installed on some Ubuntu systems (it is a screen reader that is not related to this Orca). This problem arose because the folder of Miniconda executables is at the end of my PATH environment variable, thus the /usr/bin/orca is found first.

The problem was solved after I addressed it on the Plotly forums.

I would recommend tackling this in the README.md in the Installation section or a Troubleshooting section:

##Troubleshooting: wrong executable found
If you meet issues with the orca executable not being the correct one, this may be due to another executable with the same name existing on your system. Please specify the complete path to the Plotly-Orca binary that you downloaded (for instance in the Miniconda folder) with the following command:
plotly.io.orca.config.executable = '/home/your_name/miniconda3/bin/orca'