Merge pull request #2 from eggrobin/porting-geometry-to-C++

Porting geometry to c++
Merge pull request #3 from eggrobin/porting-geometry-to-C++

Porting geometry to c++
Merge pull request #4 from eggrobin/porting-geometry-to-C++

Porting geometry to c++
All the quantities!
Screw radiometry. Come back when you have a proper unit.
Styleguide-compliant spacing.
Coherent derived units in the SI with special names and symbols
All the units!
Ref all the things!
Rename.
Rename.
Merge branch 'quantities' of https://github.com/eggrobin/Principia into quantities
Constants
Wrapping.
Photometry and radiometry.
private friends.
Effective friends.
Compiles at least...
Started making Dimensnionless the base number type.
Switching computers...