cleanup error message consistency

  relicts from the CTransaction refactor.
Merge pull request #3300

848fe68 cleanup error message consistency (Julian Langschaedel)
contrib: add sipa's github-merge script
Merge pull request #3302

e5adec3 contrib: add sipa's github-merge script (Wladimir J. van der Laan)
Merge pull request #12 from bitcoin/master

Upgrading from BitCoin