release v2.1.0

Bump version: 2.0.1.dev0 → 2.0.1

Bump version: 2.0.0 → 2.0.0.post0

Get Keithley commands at runtime (#18)

* get global variables from Lua runtime

* make all attribute access dynamic

* add KeithleyIOError to global imports

* add type hinting

* updated changelog

* improve support for reading buffers

* updated string formatting

* reset Keithley command dict on connection

* updated MagicClass repr

* update readme

* refactored error handling

* nicer repr and error message for MagicProperty

* bumped to v2.0.0.dev0