order tests

Prefix filenames so they sort in order of significance.

diff --git a/t/Functions.t b/t/10-functions.t
similarity index 100%
rename from t/Functions.t
rename to t/10-functions.t

diff --git a/t/meta.t b/t/91-meta.t
similarity index 100%
rename from t/meta.t
rename to t/91-meta.t

diff --git a/t/pod.t b/t/92-pod.t
similarity index 100%
rename from t/pod.t
rename to t/92-pod.t

diff --git a/t/pod-coverage.t b/t/93-podcover.t
similarity index 100%
rename from t/pod-coverage.t
rename to t/93-podcover.t