Merge branch 'develop' of https://github.com/stan-dev/stan into develop
Merge branch 'develop' of https://github.com/stan-dev/stan into develop
Merge branch 'develop' of https://github.com/stan-dev/stan into develop
Merge branch 'develop' of https://github.com/stan-dev/stan into develop
completes fix for issue #733, by printing warning and failing if user-defined functions contain void type arguments
fixes issue #734 by disallowing user-defined function names as variables
updating test model -- had a typo
Merge branch 'bugfix/issue-733-function-void-args' of https://github.com/stan-dev/stan into bugfix/issue-733-function-void-args
rewrote logic of void check for user-defined function args to actually fail when it should
Merge pull request #758 from stan-dev/bugfix/issue-733-function-void-args

Fixes #733. Bugfix/issue 733 function void args
fix check_cholesky_factor_corr()
refactor check_cholesky_factor_corr test

make it look like check_cholesky_factor_test
Merge branch 'develop' into bugfix/issue-734-user-fun-name-var-conflict

Conflicts:
	doc/stan-reference-2.3.0.pdf
	src/test/unit/gm/parser_test.cpp
Merge pull request #759 from stan-dev/bugfix/issue-734-user-fun-name-var-conflict

Fixes #734. Bugfix/issue 734 user fun name var conflict
Merge pull request #769 from alyst/fix_check_cholesky_corr

fix check_cholesky_factor_corr()
fix multi_gp_log() signature
sync multi_normal and multi_normal_cholesky

rearrange the code so that it is more evident which code parts
are shared and which are different between multi_normal and
multi_normal_cholesky distributions
use new variable to denote Cholesky factor

don't reuse Sigma variable to store its Cholesky factor
cleanup multi_gp

remove unused headers and 'using' directives,
update template parameter names
add multi_gp_cholesky distribution