Remove code that requires C++11 features

[federicofernandez]

To allow compilation in Windows + Python 2.7 we need to remove the use of lambdas and std::function since is not supported in the msvc compiler version for 2.7.

Fixes: https://ci.appveyor.com/project/conda-forge/pandana-feedstock/builds/27034085/job/nwh0feurg1ijv0eu

[coveralls]

Coverage remained the same at 91.667% when pulling c6ccf12 on enhancement/remove-c++11 into 20b8724 on develop.

[smmaurer]

Thanks @federicofernandez!

One of the compilation flags in setup.py specifies std=c++11. Do you think we should change that? It might not matter; i think that's been there since before the changes that broke win-py27 compilation.

https://github.com/UDST/pandana/blob/enhancement/remove-c%2B%2B11/setup.py#L54

[federicofernandez]

One of the compilation flags in setup.py specifies std=c++11. Do you think we should change that? It might not matter; i think that's been there since before the changes that broke win-py27 compilation.

I don't think is needed since those flags are used only for Linux / OSX. Anyway, the final test will be the compilation on Windows + 2.7, but I think it should work as is.

[Eh2406]

Can we make sure the performance does not regress, that we still have the gains from #111?

[federicofernandez]

Yes, no regressions, it's the same performance as #111, just with less elegant code, but more compatible.

[Eh2406]

Thanks for double checking!