Connect waveform table to rest of emap star and implement basic core proc logic

[jeremyestein]

Epic: #27

Waveform table is currently sitting in the DB unconnected to any other table. It needs to be joined up to, eg. the hospital_visit table.

• Database design
• core processor logic
  • location matching could be hard

(orphan data can hopefully stay out of scope - see #36 for that)

[jeremyestein]

Have linked waveform table to rest of DB. Need to add some fields to the interchange message to distinguish between the source location and data stream codes and the converted location and data stream descriptions, so the core processor logic can store these and use them for further links in the DB.