Log Message:
libpano13: updated to 2.9.22

There have been some changes since 2.9.21:

* Fix some insecure data handling in command-line tools, this doesn't affect
Hugin usage. In particular the ShowScript and LaunchAndSendScript functions
have been replaced with non-functional stubs. These functions are not used by
libpano13 itself and have security issues.

* Clean-up some older deprecated C code, minor build improvements

* Fixes big endian check for Mac OS

* Write TIFFTAG_EXTRASAMPLE tag for files with alpha channel