sjjaffe/cpp-opaque-typedef @ 51561c8bf20327c8727af662b3b508ddb2721e74

Sam Jaffe 7e0754c70a Fix compiler error that occurs due to include order		5 gadi atpakaļ
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arithmatic.hpp	213a23f3ad Add skills for +, -, unary -, *, /, ++, and --.	5 gadi atpakaļ
comparable.hpp	6b05c16210 Break out impl files from opaque_typedef.	5 gadi atpakaļ
opaque_typedef.hpp	7e0754c70a Fix compiler error that occurs due to include order	5 gadi atpakaļ