add irc_test.go, update Makefile and .gitignore

add simple test code to make building this package within src/pkg happy;
update irc/Makefile whitespace -- s/    /\t/;
update .gitignore to ignore _test directory created in test build;

.gitignore

@@ -1,6 +1,7 @@
 /gobot
 *.[568]
 _obj/
+_test/
 *.swp
 *~
 *.out

irc/irc_test.go

@@ -0,0 +1,15 @@
+package irc
+
+import (
+	"testing"
+)
+
+// Not really sure what or how to test something that basically requires a
+// connection to an IRC server to function, but we need some tests or when this
+// is present in the go package tree builds fail hard :-(
+func TestIRC(t *testing.T) {
+	if c := New("test", "test", "Testing IRC"); c == nil {
+		t.FailNow()
+	}
+}
+