reflect: add example for StructOf
reflect: add example for StructOf

This CL adds a simple example for StructOf.
The example shows how StructOf can be used in a JSON roundtrip.

Change-Id: I9ff1ea9cb8c0cf297c5fae74e68b89931076adfd
Reviewed-on: https://go-review.googlesource.com/33953
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: David Crawshaw <a2f0bf29257797dd66800b4fbb9945c3e216c004@golang.org>

codestation/go,Cofyc/go,nawawi/go,suncycheng/go,golang/go,polyverse-security/go,suncycheng/go,nawawi/go,linux-on-ibm-z/go,linux-on-ibm-z/go,linux-on-ibm-z/go,ImJasonH/go,suncycheng/go,codestation/go,codestation/go,golang/go,ImJasonH/go,cloudflare/go,akutz/go,polyverse-security/go,akutz/go,linux-on-ibm-z/go,vsekhar/elastic-go,CAFxX/go,suncycheng/go,vsekhar/elastic-go,nawawi/go,ImJasonH/go,cloudflare/go,ImJasonH/go,golang/go,ImJasonH/go,Cofyc/go,vsekhar/elastic-go,ImJasonH/go,josharian/go,nawawi/go,akutz/go,nawawi/go,Cofyc/go,derekmarcotte/go,christopher-henderson/Go,polyverse-security/go,josharian/go,derekmarcotte/go,derekmarcotte/go,derekmarcotte/go,ImJasonH/go,akutz/go,CAFxX/go,polyverse-security/go,josharian/go,derekmarcotte/go,linux-on-ibm-z/go,vsekhar/elastic-go,akutz/go,akutz/go,golang/go,akutz/go,CAFxX/go,golang/go,josharian/go,cloudflare/go,suncycheng/go,cloudflare/go,linux-on-ibm-z/go,vsekhar/elastic-go,josharian/go,Cofyc/go,Cofyc/go,linux-on-ibm-z/go,CAFxX/go,polyverse-security/go,akutz/go,cloudflare/go,CAFxX/go,Cofyc/go,derekmarcotte/go,codestation/go,vsekhar/elastic-go,derekmarcotte/go,cloudflare/go,nawawi/go,nawawi/go,codestation/go,Cofyc/go,polyverse-security/go,cloudflare/go,vsekhar/elastic-go,golang/go,Cofyc/go,golang/go,codestation/go,codestation/go,vsekhar/elastic-go,polyverse-security/go,nawawi/go,cloudflare/go,josharian/go,codestation/go,golang/go,linux-on-ibm-z/go,CAFxX/go,suncycheng/go,suncycheng/go,polyverse-security/go,ImJasonH/go,suncycheng/go,derekmarcotte/go,josharian/go,CAFxX/go,CAFxX/go,josharian/go