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/memcpy.untouched.wat

@@ -9,7 +9,7 @@
  (elem (i32.const 0) $null)
  (global $memcpy/base i32 (i32.const 8))
  (global $memcpy/dest (mut i32) (i32.const 0))
- (global $HEAP_BASE i32 (i32.const 32))
+ (global $~lib/memory/HEAP_BASE i32 (i32.const 32))
  (export "memory" (memory $0))
  (export "table" (table $0))
  (export "memcpy" (func $memcpy/memcpy))
@@ -1208,7 +1208,7 @@
   end
   local.get $3
  )
- (func $start (; 2 ;) (type $_)
+ (func $start:memcpy (; 2 ;) (type $_)
   global.get $memcpy/base
   i64.const 1229782938247303441
   i64.store
@@ -1428,6 +1428,9 @@
    unreachable
   end
  )
- (func $null (; 3 ;) (type $_)
+ (func $start (; 3 ;) (type $_)
+  call $start:memcpy
+ )
+ (func $null (; 4 ;) (type $_)
  )
 )