added README with installation instructions

README

+To install, please use poetry
+
+https://python-poetry.org/
+
+First, clone the repository
+
+>>> git clone https://git.ecdf.ed.ac.uk/pswain/omniplate.git ompkg
+
+then
+
+>>> cd ompkg/code
+
+and run
+
+>>> poetry install
+
+There is a jupyter notebook of an illustrative workflow, which was used
+to generate
+
+https://swainlab.bio.ed.ac.uk/software/omniplate/omniplate.html
+
+and requires the data in the data folder to do so.
+
+The notebook assumes that you have added ompkg/code to your PYTHONPATH,
+but you could instead move the notebook and data folder to the code folder.
+
+Calibration data for correcting the optical density of budding yeast
+is in the odcorrection folder. The data for haploids in glucose is
+hard coded into the software.