Upgrade datastructures

[NickMcSweeney]

Upgrade internal datastructures

this PR targets 3 areas

1. atomics: most of the atomic implementations used a deprecated set of methods. the client should be updated to use the @atomic macros
2. subscription: the dictionary storage of topics was a bit simple causing increasingly complex validations and string matching. topics are moved to a Trie data structure where callback functions are stored in a trie graph with topic pieces as keys.
3. asynchronous process management: particularly when disconnecting the read and write loops would throw errors, better process management is added to prevent loops hanging waiting for data.

Changes

• all atomics use @atomic macros
• a custom implementation of a Ordered tree data structure is created
  • on subscription a callback function is added to the trie struct based on the topic using insert!
  • on publish a callback function is looked up using get
  • on unsubscribe a callback function is removed using remove!
• an if check is added in the read loop to make sure the io is not eof
• an if check is added in the write loop to make sure there is data to write
• unit tests are updated
• precompile is updated