Rename memory instructions; Rework constant handling (#177)

* Rename memory instructions as proposed by the bulk-memory-operations spec.
* Rename memory manager functions to memory.* as well
* Remove automatic inlining of constant globals (Binaryen does this now)
* Improve 'const' enum compatibility
* Improve module-level export generation
* Enable the inline decorator for constant variables
* Add ERROR, WARNING and INFO macros that emit a user-defined diagnostic
* Reintroduce builtin decorator so these can appear anywhere in stdlib again
* Inline isNaN and isFinite by default
* Make an interface around gc.* similar to memory.*
* Emit an error when trying to inline a mutable variable
* Slim down CI stages
* Add a more convenient tracing utility for debugging
* Implement some prequesites for an eventual bundled GC

std/assembly/allocator/system.ts

@@ -10,17 +10,12 @@
 declare function malloc(size: usize): usize;
 declare function free(ptr: usize): void;
 
-@global
-export function allocate_memory(size: usize): usize {
+// Memory allocator interface
+
+@global export function __memory_allocate(size: usize): usize {
   return malloc(size);
 }
 
-@global
-export function free_memory(ptr: usize): void {
+@global export function __memory_free(ptr: usize): void {
   free(ptr);
 }
-
-@global
-export function reset_memory(): void {
-  unreachable();
-}