Tests: change directory to allow runing from outside.
Use FindBin to find out where tests reside and chdir() into it. This allows
to use configs from the directory with tests and to use _common.pm.
diff --git a/ssi-include-big.t b/ssi-include-big.t
index 6634eda..3c3b5e4 100644
--- a/ssi-include-big.t
+++ b/ssi-include-big.t
@@ -11,6 +11,8 @@
use Test::More tests => 3;
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
use _common;
###############################################################################
