upgraded travis to boost 1.55
upgraded travis to boost 1.55

dstoe/vigra,funkey/vigra,dagophil/vigra,funkey/vigra,dagophil/vigra,funkey/vigra,dagophil/vigra,dagophil/vigra,dstoe/vigra,dagophil/vigra,funkey/vigra,dstoe/vigra,funkey/vigra,dagophil/vigra,dstoe/vigra,funkey/vigra,dstoe/vigra,dstoe/vigra,funkey/vigra,dstoe/vigra,dagophil/vigra