Add Travis CI build status.
Add Travis CI build status.

Change-Id: Ia0ad3b10fc3e2617945fd0ca763f134ef7276fa4
Reviewed-on: https://swiftshader-review.googlesource.com/10088
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>
Tested-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader