test: add lots of stream tests

core-test/streams.c

@@ -0,0 +1,10 @@
+#include <blue/core/stream.h>
+#include <stdio.h>
+
+int main(void)
+{
+	b_stream_read_line_s(b_stdin, b_stdout);
+	b_stream_write_char(b_stdout, '\n');
+
+	return 0;
+}