Canopen

Since the API has been pretty stable and no real bug reports have been filed for a long time, the project could now be considered stable in the sense that we now will follow semantic versioning rules.

* Add callback for NMT slaves (158)
* More info in debug output when adding PDOs (162)
* Add unofficial support for using a custom CRC for block transfers (157)
* Fix SDO communication error printout (160)

* Basic support for 29-bit IDs (148).
* Support multiple SDO channels for a single node (148).
* Support toggle bit in received heartbeat messages (150).
* Fix bug with some manufacturer specific data types (146).
* Fix BOOLEAN support with bit mapped PDOs (104).
* Fix deprecation of collections module.
* Bump python-can requirement to 3.0.

* SDO data size truncated to length of the default value in the EDS (135)
* Prevent crash in `SyncProducer.stop()` if `Network.sync.start()` was not called (128)
* following the newly API of CIA402,do some change (132)

New features
* Partial slave node support!
* New way of accessing PDOs
* Improved DS-402 profile support
* LSS fast scan support
* Node guarding support

* Fixes bug where `node.pdo.save()` will not work after mapping PDOs using OD names.

Improves compatibility with more "exotic" CANopen implementations (most notably Curtis drives).