- Change "call" to "dialog" where use of "call" is confusing, since it may be...

- Change "call" to "dialog" where use of "call" is confusing, since it may be a register transaction or a subscription.
The word dialog is defined as "a peer-to-peer SIP relationship between two UAs that persist for some time" in RFC 3261.

- Whitespace fixes
- Debugging fixes (adding check of option_debug)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@8489 65c4cc65-6c06-0410-ace0-fbb531ad65f3