[fine] Gobs of work

- Assertion improvements
- Type check function calls
- Functions in the environment
- Compile function calls

fine/tests/expression/errors/wrong_function.fine

@@ -0,0 +1,5 @@
+fun foo(x: f64) {}
+let x = foo("hello");
+x;
+
+// @type-error: 41 parameter 0 has an incompatible type: expected f64 but got string