fixed multi_normal ONLY ONE FUNCTION SIGNATURE; fixes half of #299
fixed multi_normal tests ONLY ONE FUNCTION SIGNATURE; fixes OTHER half of #299
Merge branch 'hotfix/v2.0.1' of https://github.com/stan-dev/stan into hotfix/v2.0.1
Merge branch 'hotfix/v1.0.1' into feature/issue-299-fix-multinormal
broke multi_normal into component distributions by file with tests broken out
finishes fix for issue #299 -- unit tests for gradients of multi_normal
Merge pull request #308 from stan-dev/feature/issue-299-fix-multinormal

Fixes #299