Adding Secure Ruby Development Guide
Yeah, these files are located in their own fhosted repo
Revert "Yeah, these files are located in their own fhosted repo"

This reverts commit c3c9bf03366425589183febfa961789738a1efb1.
Custom memory allocators: Complete sentence

Also add section ID.
sect-Defensive_Coding-TLS-OpenSSL: Mention "openssl genrsa" entropy issue
RPM packaging: X.509 key pair generation
TLS: More balanced advice on "openssl genrsa" and /dev/urandom