Rename _screed_record_dict calls in khmer

[ctb]

Fix issue #767; taken over from #956.

Added support for changes in screed - need to have correct screed version in order to work
Passes test when specifying the screed version.

• Is it mergeable?
• Did it pass the tests?
• If it introduces new functionality in scripts/ is it tested?
  Check for code coverage with make clean diff-cover
• Is it well formatted? Look at make pep8, make diff_pylint_report,
  make cppcheck, and make doc output. Use make format and manual
  fixing as needed.
• Did it change the command-line interface? Only additions are allowed
  without a major version increment. Changing file formats also requires a
  major version number increment.
• Is it documented in the ChangeLog?
  http://en.wikipedia.org/wiki/Changelog#Format
• Was a spellchecker run on the source code and documentation after
  changes were made?
• Is the Copyright year up to date?

[ctb]

Needs to wait for the next release of screed, sadly.

[luizirber]

I'm taking over this and bringing #1045 changes too.

(#1045 did this change, but there other fixes needed for screed 0.9)

[luizirber]

OK, at this point both me and Titus touched the PR, so ready for review and merge @mr-c @camillescott

[mr-c]

LGTM, thanks!