TCPError only returns a description, not a proper Error code

[jabwd]

The value of _code in the TCPError returned is always 1, therefore forcing a developer to compare the description string in order to see what really happened.

-- Side note: This will most likely be a part in a series of some issue reports while I'm wrapping libevent around this library, I am not sure whether I'll get it pretty enough for a pull request though ( I'm time limited ).