changed cyclic dep detection

since interpolation can be used, detection should be a execution time,
and not before

now, to prevent infinite execution, there's a miximum of 100 calls per
task

closes #37

testdata/cyclic/Taskfile.yml

@@ -0,0 +1,7 @@
+task-1:
+  deps:
+    - task: task-2
+
+task-2:
+  deps:
+    - task: task-1