This patch is mostly a reorganization of existing code with a few exceptions:
* Added doxygen comments to all of the extracted functions.
* Split reload_firmware(int unload) into iax_firmware_reload() and
iax_firmware_unload() for readability.
* Create iax_firmware_traverse() to support the 'iax2 show firmware' CLI
command.
* Renamed iax_check_version() to iax_firmware_get_version() and change its
arguments and return value so that it returns a success/failure value and sets
the selected version into an out parameter to avoid confusion with failure and
version 0.
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@380695 65c4cc65-6c06-0410-ace0-fbb531ad65f3
