Issue with initialization loop in tt1

[ledongthuc]

When I try and build the example of tt1 from go install github.com/yob/pdfreader/tt1. I got an error:

# github.com/yob/pdfreader/type1
../../../yob/pdfreader/type1/type1.go:269: initialization loop:
	/Users/thucle/.gvm/pkgsets/go1.8/global/src/github.com/yob/pdfreader/type1/type1.go:269 Ops refers to
	/Users/thucle/.gvm/pkgsets/go1.8/global/src/github.com/yob/pdfreader/type1/type1.go:107 (*TypeOneI).op_ifelse refers to
	/Users/thucle/.gvm/pkgsets/go1.8/global/src/github.com/yob/pdfreader/type1/type1.go:278 proceed refers to
	/Users/thucle/.gvm/pkgsets/go1.8/global/src/github.com/yob/pdfreader/type1/type1.go:269 Ops