"multithreaded" build execution

[Mike-7]

A must have feature, I think.

Example:
Suppose we have some very long build action which requires lengthy disk I/O operations or even network calls (e.g. remote telnet session on unix machine). This step can be easily built simultaneously with other actions.

Current state:
That's ok - Visual Builder has an option of asynchrounous build step execution - "Wait for completion" checkbox in some types of actions (e.g. Run Program). But there no way to synchronize build execution at a later point, basically a "join" operation for build steps. For example, synchronization is needed when all binaries are built, and setup program must composed now.

Workaround:
Asynchronous build step can create some disk file upon completion and Visual Builder's 'wait' action can wait for creation of that file. But this is tricky, not obvious and sometimes buggy (e.g. action failed or hung and file will never be created).

Feature:
Add an option to 'Wait' action: "wait until async build step is completed" (with 'step name' parameter). The action will wait (w/ optional timeout) until previously started synchronous build step is completed.