Remove travis Docker cache (#121)
Remove travis Docker cache (#121)

* Remove travis Docker cache

See how this affects CI build time.

* Update .travis.yml

FFIG/ffig,FFIG/ffig,FFIG/ffig,jbcoe/C_API_generation,jbcoe/C_API_generation,FFIG/ffig,FFIG/ffig,jbcoe/C_API_generation,FFIG/ffig,FFIG/ffig,FFIG/ffig,jbcoe/C_API_generation