[Doc] Add recommended citation for Cantera

Cherry-pick of trunk r3033.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3149 02a645c2-efd0-11dd-984d-ab748d24aa7e
[ck2cti] Allow the case where a reaction section is specified but empty

Cherry-pick of trunk r3045.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3150 02a645c2-efd0-11dd-984d-ab748d24aa7e
[Doc] Fix names of the physical constants in the Cython documentation

Cherry-pick of trunk r3047.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3151 02a645c2-efd0-11dd-984d-ab748d24aa7e
[1D] Fix mass flux reported by Inlet1D for freely-propagating flames

Cherry-pick of trunk r3066.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3152 02a645c2-efd0-11dd-984d-ab748d24aa7e
Allow auto conversion of Python examples on Windows

3to2 cannot be called as an executable on Windows, but it can be called
as a script. Assume that the 3to2 script is installed in
PYTHONROOT\Scripts, which is the default for installation by pip.

Cherry-pick of trunk r3113.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3153 02a645c2-efd0-11dd-984d-ab748d24aa7e
[Doc] Add installation instructions for Windows binaries

Cherry-pick of trunk r3131.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3154 02a645c2-efd0-11dd-984d-ab748d24aa7e
[Doc] Add OS X installation instructions using Homebrew

Cherry-pick of trunk r3132.

Conflicts:
	doc/sphinx/faq.rst

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3155 02a645c2-efd0-11dd-984d-ab748d24aa7e
Bump version to 2.1.2

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@3156 02a645c2-efd0-11dd-984d-ab748d24aa7e