Updates from kpe-core

Fix python code generator. Update CI docker image

Default EventEmitter is safe.

Fixes to DDS builds and cmake

Updated to Apache 2.0 license

Fix publication stats. Fix pip install

Updated DataMultiplexer API, new event emitters

- Add publish/subscriber with shared ptrs
- set start time stamp to container start time. Fix naming
- add shared pointer listener and fix eventloop pool release issue
- New set of event emitters
- Update event loop to use unique ptr for scheduler
- Add event emitter benchmarks
- Rewrite Listener base class to prevent unnecessary checks
- Update benchmarks to use container
- DataMultiplexer Subscriber spawns threads intead of listeners.
- Adds discardEvents method to eventEmitter
- Add removeAllListeners method
- Fix typo in function stats
- Add container start stop tests
- Update kpsr-build to latest
- Use git tags to set klepsydra version
- Add options to enable/disable examples and unit tests
- Add cmake format
- Ignore version files from git
- Add Version and API version (SOVERSION) to generated libraries
- Bugfix install rule
- Use cmake module for setting build mode
- Use strings in version file if git tags not available
- Add position independent code option
- Fix cmake to build and install kpsr-codegen only if changed
- Add build version of codegen for codegen test
- Update object pool publisher to reduce nullptr checks

Bumped version to 4.0.0

Bumped version to 3.3.0

Use atomic checks better to prevent event loop from starting twice (#59)

Fix memory leak in DDS, fix unit tests (#58)

Fix potential memory leak in dds environment
Use test fixture to ensure proper shutdown on failure