Fix concurrency issues (#142)

* Fix the OS FD error

* Cache the compiler versions

* Allow for auto display impl in declare wrapper type macro

* Better logging and fix concurrency issues

* Fix tests

* Format

* Make the code even more concurrent

crates/compiler/src/lib.rs

@@ -47,7 +47,7 @@ pub trait SolidityCompiler {
         version: impl Into<VersionOrRequirement>,
     ) -> impl Future<Output = anyhow::Result<PathBuf>>;
 
-    fn version(&self) -> anyhow::Result<Version>;
+    fn version(&self) -> impl Future<Output = anyhow::Result<Version>>;
 
     /// Does the compiler support the provided mode and version settings?
     fn supports_mode(