Add model and serd-sort utility

With all the new functionality, the complexity of the serd-pipe command-line
interface is starting to push the limits of available flags. So, instead of
grafting on further options to control a model, this commit adds a new tool,
serd-sort, which acts somewhat like a stripped-down serd-pipe that stores
statements in a model in memory.

This keeps the complexity (including the user-facing complexity) of any one
tool down, since other more focused tools can be used for streaming tasks in a
pipeline.

In other words, abandon Swissarmyknifeism, take a page from the Unix
philosophy, and try to expose the model functionality to the command-line in a
dedicated focused tool.  The model implementation is tested by using this tool
to run a subset of the usual test suites, and a special suite to test statement
sorting.

1 files changed, 22 insertions, 0 deletions

diff --git a/test/sort/input.trig b/test/sort/input.trig
new file mode 100644
index 00000000..9561d9b8
--- /dev/null
+++ b/test/sort/input.trig
@@ -0,0 +1,22 @@
+@prefix eg: <http://example.org/> .
+
+eg:graph1 {
+	eg:s
+		a eg:Subject ;
+		eg:blank [
+			a eg:Anonymous ;
+			eg:with eg:aProperty ,
+				eg:orAnother
+			] ;
+		eg:list (
+			1
+			2
+		) ;
+		eg:literal "s1" .
+}
+
+eg:graph2 {
+	eg:a
+		a eg:OtherSubject ;
+		eg:b eg:c .
+}