Remove travis ci badge which no longer works
Remove travis ci badge which no longer works

It's still red, even though the build of master has been green for
more than 24 hours.

ifeelgoods/paper_trail,theRealNG/paper_trail,jnstq/paper_trail,jnstq/paper_trail,airblade/paper_trail,devonestes/paper_trail,ifeelgoods/paper_trail,theRealNG/paper_trail,airblade/paper_trail