change term "Snapshot" to FullView in publishing tab

[lmckenzi]

(from https://jira.hl7.org/browse/FHIR-19967)

Rename the "Snapshot" tab to "Full Structure".

Add a line at the top of of the snapshot that says:
"This provides the consolidated view (aka snapshot) of the profile after applying the changes in this profile to the base [x] profile."

Adjust the text at the top of the differential tab to say:
"This indicates the differences between this profile and the base [x] profile"

As an alternative, change the core publisher to use the IG publisher for all profiles (which would probably be a good idea for other reasons).