Strip out old code

All of these files have been moved to either:

- https://github.com/sigp/lighthouse-beacon
- https://github.com/sigp/lighthouse-validator
- https://github.com/sigp/lighthouse-common

For rationale, see: https://github.com/sigp/lighthouse/issues/197

eth2/utils/slot_clock/src/testing_slot_clock.rs

@@ -1,48 +0,0 @@
-use super::SlotClock;
-use std::sync::RwLock;
-use types::Slot;
-
-#[derive(Debug, PartialEq)]
-pub enum Error {}
-
-/// Determines the present slot based upon the present system time.
-pub struct TestingSlotClock {
-    slot: RwLock<u64>,
-}
-
-impl TestingSlotClock {
-    /// Create a new `TestingSlotClock`.
-    ///
-    /// Returns an Error if `slot_duration_seconds == 0`.
-    pub fn new(slot: u64) -> TestingSlotClock {
-        TestingSlotClock {
-            slot: RwLock::new(slot),
-        }
-    }
-
-    pub fn set_slot(&self, slot: u64) {
-        *self.slot.write().expect("TestingSlotClock poisoned.") = slot;
-    }
-}
-
-impl SlotClock for TestingSlotClock {
-    type Error = Error;
-
-    fn present_slot(&self) -> Result<Option<Slot>, Error> {
-        let slot = *self.slot.read().expect("TestingSlotClock poisoned.");
-        Ok(Some(Slot::new(slot)))
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_slot_now() {
-        let clock = TestingSlotClock::new(10);
-        assert_eq!(clock.present_slot(), Ok(Some(Slot::new(10))));
-        clock.set_slot(123);
-        assert_eq!(clock.present_slot(), Ok(Some(Slot::new(123))));
-    }
-}