fixed #264. fixed 'build' target in makefile
updating makefile doc
quoting the path separators
adding indicator that Stan tools were built
Merge pull request #265 from stan-dev/feature/issue-264-makefile-build-target

Fixes #264.
Merge branch 'feature/issue-211-stan2-manual' of https://github.com/stan-dev/stan into feature/issue-211-stan2-manual
Merge branch 'develop' of https://github.com/stan-dev/stan into feature/issue-211-stan2-manual
fixed more issues in manual