Plan/apply -replace and -refresh=false options are missing

[thrashr888]

There's a couple of new plan features that could use support added to this lib:
https://www.terraform.io/docs/cli/commands/plan.html#planning-options

[radeksimko]

refresh option is already supported for both apply and plan command:

terraform-exec/tfexec/apply.go

Lines 72 to 74 in 7fa6ba6

	func (opt *RefreshOption) configureApply(conf *applyConfig) {
	conf.refresh = opt.refresh
	}

terraform-exec/tfexec/plan.go

Lines 62 to 64 in 7fa6ba6

	func (opt *RefreshOption) configurePlan(conf *planConfig) {
	conf.refresh = opt.refresh
	}

I just raised #211 to add the missing replace argument/option.