import oap message parsing / encoding from openbsc.git; AGPL->GPL

In the process, also:
* Change the license from AGPLv3 to GPLv2-or-later;
* correct spelling of 'sysmocom' to lowercase;
* add '2016' to the copyright;
* rename to osmo_*;
* add API docs;
* add logging category DLOAP: define id and add to internal_cat;
* redirect all oap.c logging to DLOAP.

A unit test will follow in a subsequent patch, since it needs a minor tweak for
decoding of boolean values.

The related openbsc change-id is I2f06aaa6eb54eafa860cfed8e72e41d82ff1c4cf.

Tweaked-by: Neels Hofmeyr
Change-Id: If5099e60681a215e798b6675f21813f26769c253
diff --git a/src/logging.c b/src/logging.c
index 30d0b8d..92852c9 100644
--- a/src/logging.c
+++ b/src/logging.c
@@ -128,6 +128,11 @@
 		.description = "Generic Subscriber Update Protocol",
 		.enabled = 1, .loglevel = LOGL_NOTICE,
 	},
+	[INT2IDX(DLOAP)] = {
+		.name = "DLOAP",
+		.description = "Osmocom Authentication Protocol",
+		.enabled = 1, .loglevel = LOGL_NOTICE,
+	},
 };
 
 /*! \brief descriptive string for each log level */