work on issue #102
Merge branch 'develop' of https://github.com/stan-dev/rstan into develop
change travis config to allow gcc to fail
Merge branch 'develop' of https://github.com/stan-dev/rstan into develop

Conflicts:
	rstan/rstan/R/rstan.R
	rstan/rstan/R/stanmodel-class.R
Merge branch 'develop' of https://github.com/stan-dev/rstan into develop