Remove mentions of Python 2.5 and 'from __future__ import with'
Update copyright years.
Merge pull request #31 from mdickinson/fix/remove-future-with

Remove mentions of Python 2.5 and 'from __future__ import with'
Merge pull request #32 from mdickinson/update-copyright

Update copyright years.
Fix mpfr_get_version and MPFR_VERSION_STRING to be str rather than unicode on Python 2.
Document MPFR_VERSION* constants.
Add test comparing mpfr_get_version() output with MPFR_VERSION_STRING.
Merge pull request #35 from mdickinson/fix/mpfr-version-str

Fix/mpfr version str
Merge remote-tracking branch 'origin/master' into fix/grammar-nit