HOTFIX: Reset the initial paramaters on LK

When performing a single fitting of LK, we weren't resetting the
parameters. Luckily, this is a simple fix.
Merge branch 'master' into lk_hotfix
Extends the hotfix to CLMs and parametric-based SDMs
Merge pull request #348 from patricksnape/lk_hotfix

HOTFIX: Reset the initial paramaters on LK