Re-structure sat-rs

- Add new shared subcrate satrs-shared to split off some shared
  components not expected to change very often.
- Renmame `satrs-core` to `satrs`. It is expected that sat-rs will remain
  the primary crate, so the core information is superfluous, and core also
  implies stability, which will not be the case for some time.

satrs/tests/pools.rs

@@ -0,0 +1,38 @@
+use satrs::pool::{PoolGuard, PoolProvider, StaticMemoryPool, StaticPoolConfig, StoreAddr};
+use std::ops::DerefMut;
+use std::sync::mpsc;
+use std::sync::mpsc::{Receiver, Sender};
+use std::sync::{Arc, RwLock};
+use std::thread;
+
+const DUMMY_DATA: [u8; 4] = [0, 1, 2, 3];
+
+#[test]
+fn threaded_usage() {
+    let pool_cfg = StaticPoolConfig::new(vec![(16, 6), (32, 3), (8, 12)], false);
+    let shared_pool = Arc::new(RwLock::new(StaticMemoryPool::new(pool_cfg)));
+    let shared_clone = shared_pool.clone();
+    let (tx, rx): (Sender<StoreAddr>, Receiver<StoreAddr>) = mpsc::channel();
+    let jh0 = thread::spawn(move || {
+        let mut dummy = shared_pool.write().unwrap();
+        let addr = dummy.add(&DUMMY_DATA).expect("Writing data failed");
+        tx.send(addr).expect("Sending store address failed");
+    });
+
+    let jh1 = thread::spawn(move || {
+        let addr;
+        {
+            addr = rx.recv().expect("Receiving store address failed");
+            let mut pool_access = shared_clone.write().unwrap();
+            let pg = PoolGuard::new(pool_access.deref_mut(), addr);
+            let mut read_buf: [u8; 4] = [0; 4];
+            let read_bytes = pg.read(&mut read_buf).expect("Reading failed");
+            assert_eq!(read_buf, DUMMY_DATA);
+            assert_eq!(read_bytes, 4);
+        }
+        let pool_access = shared_clone.read().unwrap();
+        assert!(!pool_access.has_element_at(&addr).expect("Invalid address"));
+    });
+    jh0.join().unwrap();
+    jh1.join().unwrap();
+}