performance and code size improvements

- Use default case for constructors with no explicit match.
- self-compile is 15s now
- code size is 60% smaller

code size and self compile time on par with the idris-built version

src/Lib/CompileExp.idr

@@ -116,6 +116,7 @@ compileTerm (Meta _ k) = pure $ CRef "meta$\{show k}" -- FIXME
 compileTerm (Lam _ nm _ _ t) = pure $ CLam nm !(compileTerm t)
 compileTerm tm@(App _ _ _) with (funArgs tm)
   _ | (Meta _ k, args) = do
+        error (getFC tm) "Compiling an unsolved meta \{showTm tm}"
         info (getFC tm) "Compiling an unsolved meta \{showTm tm}"
         pure $ CApp (CRef "Meta\{show k}") [] Z
   _ | (t@(Ref fc nm _), args) = do