Recommend PascalCase for class names (not camelCase)

[Mark2Mark]

GlyphsSDK/Python Templates/README.md

Line 26 in 8d3fcc8

* `____PluginClassName____` is the machine readable name of the Python class in your code and needs to be put into a few places. It needs to be unique, as in: You can’t install two plug-ins next to each other that have the same class name. Although I wrote "machine readable", there is one interaction where the user of the plug-in will get to see this class name: Calling Filters through Custom Parameters upon file export. So make it a friendly and unique name. Only ASCII characters and no spaces allowed here. We recommend `camelCaseNames`.

End of line recommends camelCase, which should be better PascalCase, as it is the norm for Python Classes.