build: update Travis to build/test against go 1.7 + go 1.6.3
build: update Travis to build/test against go 1.7 + go 1.6.3

LightningNetwork/lnd,aakselrod/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,LightningNetwork/lnd,aakselrod/lnd,bryanvu/lnd,ddustin/lnd,AndrewSamokhvalov/lnd,bryanvu/lnd