Setup solution, added ability to use own proxy list

Created a visual studio solution including a Main() method to test the
proxypool class. Added the ability to instantiate the Getter with your
own proxy list rather than looking for a text file
Use streams

ProxyPool Getter now returns a dictionary of streams rather than just
loading Xmldocs
Added retry functionality

Added the option to turn off retries
Fixed retry functionality

If retries are off we would get stuck in an infinite loop. Fixed so that
we keep track of which clients are busy requesting resources if retries
are turned off
Fixed webclient list

Webclient list wasn't instantiated. Added cleanup code (which we might
not need)