Remove all code in binary

The `main.rs` file was used to test early on, but now the `examples` are
used for that purpose. They demonstrate how the library can be used by
another crate and are a better placement for what what previously in
`main.rs`.

The idea of the `main.rs` binary version of the crate going forward is
that it will hold a CLI for interacting with a running Parsnip system.
For example to manually send commands or inspect the state of the queue.

Author: magnunm

src/main.rs

@@ -1,89 +1,3 @@
-use anyhow;
-use parsnip::{
-    self, broker::Broker, messages::Message, messages::ResultMessage, task::Signature, task::Task,
-    worker::Worker,
-};
-use std::collections::LinkedList;
-use std::sync::RwLock;
-
-struct InMemoryTestBroker {
-    task_results: RwLock<Vec<ResultMessage>>,
-    queue: RwLock<LinkedList<Message>>,
-}
-
-impl InMemoryTestBroker {
-    fn new() -> Self {
-        Self {
-            task_results: RwLock::new(Vec::new()),
-            queue: RwLock::new(LinkedList::new()),
-        }
-    }
-}
-
-impl Broker for InMemoryTestBroker {
-    fn push_message(&self, message: &Message) -> anyhow::Result<()> {
-        self.queue
-            .write()
-            .expect("Failed to aquire lock")
-            .push_back(message.clone());
-        Ok(())
-    }
-
-    fn pop_message(&self) -> anyhow::Result<Option<Message>> {
-        match self
-            .queue
-            .write()
-            .expect("Failed to aquire lock")
-            .pop_front()
-        {
-            Some(message) => Ok(Some(message)),
-            None => Ok(None),
-        }
-    }
-
-    fn store_result(&self, result_message: ResultMessage) -> anyhow::Result<()> {
-        self.task_results
-            .write()
-            .expect("Failed to aquire lock")
-            .push(result_message.clone());
-        Ok(())
-    }
-}
-
-struct HelloWorldTask {
-    called_with_signature: Signature<Self>,
-}
-
-impl Task for HelloWorldTask {
-    type ArgumentType = ();
-    type ReturnType = ();
-
-    const ID: &'static str = "HelloWorldTask";
-
-    fn from_signature(signature: Signature<Self>) -> Self {
-        Self {
-            called_with_signature: signature,
-        }
-    }
-
-    fn run(_: &Self::ArgumentType) -> Self::ReturnType {
-        println!("Hello, World!");
-    }
-
-    fn signature(&self) -> &Signature<Self> {
-        &self.called_with_signature
-    }
-}
-
-fn main() -> Result<(), anyhow::Error> {
-    let mut broker = InMemoryTestBroker::new();
-    let mut app = parsnip::App::new(&mut broker);
-    app.register_task::<HelloWorldTask>();
-
-    let worker = Worker::new(&app);
-
-    app.queue_task::<HelloWorldTask>(())?;
-    worker.take_first_task_in_queue()?;
-
-    Ok(())
+fn main() {
+    println!("This binary is for the Parnsip CLI. Nothing to see here yet...")
 }