N209: Add macOS CI to Travis config. (PR #215, Issue #209)
N209: Add macOS CI to Travis config. (PR #215, Issue #209)

This change adds a macOS build to the Travis CI build matrix.

Closes #209.
FFIG/ffig,FFIG/ffig,FFIG/ffig,jbcoe/C_API_generation,FFIG/ffig,FFIG/ffig,FFIG/ffig,jbcoe/C_API_generation,FFIG/ffig,jbcoe/C_API_generation,FFIG/ffig,jbcoe/C_API_generation