Add two Parameters to the autoconf and automake scripts for building the go bindings

The parameter GCCGOFLAGS can be used to pass parameters to gccgo, the
SWIGGOPARAMS parameter can be used to pass parameters to swig for
building the go bindings. SWIGGOPARAMS defaults to "-intgosize 32",
GCCGOFLAGS is empty by default. Both Paramters are required for building
the bindings under Ubuntu 12.04.

Also added a travis-ci test for the go bindings.