Import the new logging architecture

This is the new logging architecture, including

* support for multiuple logging targets like stderr and vty
* log levels in addition to categories/subsystems
* filtering based on imsi, i.e. only see events for one subscriber
* dynamically change log level for each category for each vty
diff --git a/openbsc/tests/debug/Makefile.am b/openbsc/tests/debug/Makefile.am
index 0cdf46a..62c906e 100644
--- a/openbsc/tests/debug/Makefile.am
+++ b/openbsc/tests/debug/Makefile.am
@@ -1,4 +1,4 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
 noinst_PROGRAMS = debug_test
 
-debug_test_SOURCES = debug_test.c $(top_srcdir)/src/debug.c
+debug_test_SOURCES = debug_test.c $(top_srcdir)/src/debug.c $(top_srcdir)/src/talloc.c