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
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
fix test for Windows vs. not Windows

Old version was broken when cross-compiling
get cross-compiling working again
define, test, and use a sign() function
fix the runtest no fail target
Merge branch 'develop' of https://github.com/stan-dev/stan into develop
's/EXPECT_FLOAT_EQ/EXPECT_NEAR/g'
Merge branch 'develop' of https://github.com/stan-dev/stan into develop
add make/local
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