Handle different start and end times of components

• connect and _connect get an argument start_time that is to be passed to try_connect instead of self.time
• Connect helper pushes data twice: once for start_time and once for info.time (if it is not equal to start_time)
• Starting time can be passed to component's run(), and is auto-determined if not provided

Basically, only the changes in interfaces.py, schedule.py, component.py and connect_helper.py are of interest. The rest is fixes for the breaking change to the interface.

Fixes #4 (closed)

benchmarks/adapters/test_regrid.py

@@ -25,8 +25,8 @@ class TestRegrid(unittest.TestCase):
         self.source.outputs["Step"] >> self.adapter
 
         self.adapter.get_info(fm.Info(None, grid=grid2))
-        self.source.connect()
-        self.source.connect()
+        self.source.connect(time)
+        self.source.connect(time)
         self.source.validate()
 
     @pytest.mark.benchmark(group="adapters-regrid")