Add Exhaust/Consume operator

[GoogleCodeExporter]

An Exhaust operator exists in the test project. It should be offered as a 
public operator in the base library.

Rationale: There is already ForEach and Exhaust is just the loop factored 
out, permitting consumption of a source without side-effect where needed. 
Together with Pipe, ForEach can be implemented in terms of Pipe plus 
Exhaust.

Also, while we're at it, consider Consume versus Exhaust. ;)

Original issue reported on code.google.com by azizatif on 17 Feb 2009 at 11:42

[GoogleCodeExporter]

Yup, Consume is better than Exhaust.

Original comment by jonathan.skeet on 20 Feb 2009 at 9:39

• Changed state: Started

[GoogleCodeExporter]

Done in r53.

Original comment by jonathan.skeet on 20 Feb 2009 at 9:56

• Changed state: Fixed