[Freeswitch-docs] Stable is now RELEASE

Per the core development team the word "stable" is BANNED and PROHIBITED from FreeSWITCH. The correct word to use is "RELEASE". By naming a release of code as "stable" people expected it to be free of bugs. This has never been true. It simply means that the code is not being actively developed with new features. So now, please call the numbered releases a "RELEASE", such as production release version 1.4 to keep the documentation consistent. Thank you. Bote Docs Team