Added deadlines to all algorithms (#18)

This adds a deadline to all algorithms which lets one bail in a fixed amount of
time to avoid pathological cases.

src/algorithms/snapshots/similar__algorithms__myers__deadline_reached.snap

@@ -0,0 +1,22 @@
+---
+source: src/algorithms/myers.rs
+expression: d.into_inner().ops()
+---
+[
+    Equal {
+        old_index: 0,
+        new_index: 0,
+        len: 10,
+    },
+    Replace {
+        old_index: 10,
+        old_len: 41,
+        new_index: 10,
+        new_len: 41,
+    },
+    Equal {
+        old_index: 51,
+        new_index: 51,
+        len: 49,
+    },
+]