Add Travis CI script.
Add Travis CI script.

Build for stable, beta and nightly. Allow beta and nightly to fail.

Signed-off-by: Kaustav Das Modak <ba1ce5b1e09413a89404909d8d270942c5dadd14@yahoo.co.in>

kaustavdm/gauge-rs,getgauge-contrib/gauge-rs,getgauge-contrib/gauge-rs,kaustavdm/gauge-rs