Version 1.3 release preparation

[AlexTate]

The following additional changes have been made:

• Plots have been updated in the documentation to reflect Tai's preferred plot styles, the new tick placement routine in scatter plots, and the new sorting order of scatter plot legends
• Binary file extensions are indicated in .gitattributes
• CSVReader loops in tiny-count have been wrapped in a try/except block that indicates the filename and line number where an exception occurred. In v1.4 the SamplesSheet and FeaturesSheet classes will be added to tiny-count which will add more thorough validation and exception handling. This is a stopgap until then.
• More consistent handling of exceptions when additional information needs to be appended to the error message. Previously this was inconsistent between contexts and too scattered. Now it's consistent and centralized for better maintainability

[AlexTate]

Additional changes:

• Run Config backward compatibility definitions have been completed for v1.2.1 and 1.3.0. Testing with prior version config files produced the expected outputs for both versions. Doing a two-version jump from 1.2.0 also produced the expected outputs.
• Run Config files and setup.py have been updated to report the current version as 1.3.0

[taimontgomery]

Tested with ram1 and Lib303 data.