Rework resolver (#489)

* Rework IR and resolver to use nested lookup tables
* Integrate types into IR
* Make components prefer IR, slimmed down AST
* Implement `export *`
* Add `@lazy` annotation and remove `--noTreeShaking`
* Add `@start` annotation and remove magic `main`
* Related refactoring, cleanup and docs

tests/compiler/std/gc-array.ts

@@ -20,4 +20,5 @@ arr[0] = {};
 
 gc.collect(); // should collect the old one
 
+@start
 export function main(): i32 { return 0; }