INFO-based DTMF fixes

Fixes #137
- Queue additional DTMF sends
- Fix inter-tone timing
- Insert a pause if the next tone is a comma
Grammar - join escaped characters into string
Leave eof unchanged
Merge pull request #138 from crocodilertc/issue-137

INFO-based DTMF fixes
Merge pull request #145 from wakamoleguy/escaped_strings

Grammar Fix. -Join escaped characters into string
Merge pull request #141 from egreenmachine/master

Fix "Object #<Object> has no method 'onIceCompleted'"
- when caller cancel the call.