Version 1.2 release preparation

[AlexTate]

• Bugfix: non-differentially expressed features are misrepresented in scatter_dge_class plots under certain conditions
• Bugfix: the size of an empty StepVector differs between the HTSeq StepVector and our Cython StepVector, meaning that tiny-count runs aren't handled properly when there are no Stage 1 matches (this should be an error)
• Bugfix: changes to the Paths File between recount/replot runs are not reflected
• Bugfix: cwltool issues a notice of duplicate parameter names in tiny-plot.cwl
• Add a version parameter to the Run Config so that processed run configs are automatically updated with the tinyRNA version that was used
• Add Matplotlib documentation link in the .mplstyle template stylesheet
• Add the keyword "any" to the list of wildcard keywords permitted in selection rules
• Add a diagram that demonstrates Stage 1-3 selection to the documentation
• Add documentation notes about Run Directory files that can be safely removed to reduce storage usage
• Update version number in setup.py
• Update TUTORIAL.md with corrected line number references for paths.yml