add check_positive_finite with tests
replace check_positive and check_finite with check_positive_finite
fixed missing using statement
add missing include
removed confusing 'Error in function' from exceptions
fix merge conflict
removed .orig file
Merge branch 'develop' into feature/issue-800-check-positive-finite
Merge pull request #814 from stan-dev/feature/issue-640-update-error-message

removed confusing 'Error in function' from exceptions
Merge pull request #809 from stan-dev/feature/issue-800-check-positive-finite

Feature/issue 800 check positive finite
merge develop
switch to check_positive_finite in frechet distr file
fixed lower bound test for frechet distr