reciprocalspaceship 0.9.4

• #40 Add rs.read_csv() to support plain text input sources to DataSet
• #42 Update supported Pandas versions
• #44 Add merging example to documentation using PyTorch to assess error models
• #45, #46, #48 Improve French-Wilson scaling algorithm and testing to assess accuracy
• #47 Add DataSet.centrics and DataSet.acentrics accessors