Add termination char to every segment, even the last one.

[micred]

HL7 Inspector notifies:

Warning: Last segment have no segment termination char 0x0d !

The to_hl7 - and then to_mllp - methods does not terminate the last segment.

HL7 specification says that every segment should be terminated, even the last one.
With this simple PR every segment is terminated.

[mogox]

Hey @micred, this breaks a lot of test. Would you mind taking a look at that? My guess is that we would be needing to update the test if we decide to go with this change.

Maybe we need to setup a different delimiter for test?

[micred]

Test are comparing to the wrong terminating segments:
https://travis-ci.org/ruby-hl7/ruby-hl7/jobs/146315226

The is also a \n that should not be present, do you agree?
If you'd like, I can provide a fix for newline and correct the termination in the tests.

[mitch-lindsay]

This will generate HL7 that the gem won't be able to parse. #3 The parser has trouble with a trailing newline on the last segment, treating it like a new, empty segment and throwing a HL7::EmptySegmentNotAllowed error. Not saying you shouldn't do this but if you're going to address one, it would be great to address the other.