added template parameter for dom_err_vec to handle indexing
adding test for 0 vs 1 indexing within dom_err_vec
updating with failing tests for 1-indexed error messages
updating spec and test for check_positive_ordered
updating spec and test for check_positive
removing duplicate name in error message
adding tests for 1-indexed messages in matrix checks
adding error_index as a trait
updated all code so it is 1-indexed
Merge branch 'develop' into feature/issue-331-error-message-1-indexed

Conflicts:
	src/test/unit/math/error_handling/matrix/check_ordered_test.cpp
	src/test/unit/math/error_handling/matrix/check_positive_ordered_test.cpp
Merge branch 'develop' into feature/issue-331-error-message-1-indexed
fixing call to dom_err_vec
added a ifdef for ERROR_INDEX
adding test for 1-indexed check_corr_matrix message
Merge pull request #746 from stan-dev/feature/issue-331-error-message-1-indexed

Fixes #331. Feature/issue 331 error message 1 indexed