Make references to Adapter/Interface consistent

[MikeHart85]

The disambiguation term Interface was introduced rather hastily during the communication layer redesign and 1.0 release.

Consequently, a lot of back-end code still uses incorrect terminology. This should be updated to be consistent throughout.

Terminology:

• Adapter: Functionality provided by the framework to abstract interaction with shared transport protocols (EPICS, TCP Stream, etc).
• Interface: Functionality provided by simulated device to implement specific device protocol(s) based on adapter(s).

Terminology should be updated in code, as well as comments and documentation headers.