[MAT-407] Get rid of DispatchToOGTerminal

It is replaced with JavaTerminal, which does not use the visitor.
This removes the last use of the visitors.
[MAT-407] Delete Visitor
[MAT-407] Add missing JavaTerminal exception checks
[MAT-407] Fixes in response to PR comments

- Removal of obsolete FIXME
- JavaTerminal inherits from Uncopyable instead of deleting its
  copy assignment and constructor.
[MAT-407] Use unique_ptr to manage jint arrays
Merge pull request #117 from OpenGamma/MAT-407

Replace DispatchToOGTerminal with JavaTerminal and remove the visitor