Make sure account description contains something

It contains either the value inserted into the description field or
the SIP adress.
Display account description on the botton of the call window
Account description fixup
Display account info only if more than one account is active
Fix an issue with not disabled redial button

Ended controller's view was not yet created, and its subview, redial
button, was nil.

Fixes #76
Increase delay for re-enabling redial button
Trim whitespaces and newlines in call destination strings

Fixes #85
Enable App Sandbox
Fix an issue with non-built-in default devices

When no audio devices for input, output, or ringtone have been
selected, we want to use first met built-in devices with appropriate
capabilities (with non-zero number of input channels for import, and
similar rule for output).

Originally, the OS API didn't allow to tell if the device is
built-in. Not it allows.

Fixes #71
Set deployment target to 10.8
Use OS X user notifications instead of Growl

Closes #87
Update settings of xib files

* Set "Opens in" to "Default (5.0)".
* Set "Builts for" to "Project Deployment Target (10.8)".
Add an ability to use only G.711 codec

Fixes #68
Update project to recommended by Xcode settings
Fix variable type
Fixes an issue with wrong buffer length

Fixes #61
Add support for ABCD DTMF signals

Closes #47
Update iTunes header
Update entitlements to allow iTunes playback control
Update PJSIP librarires for the latest OS X release