Prevent Panic'ing on Timeout

[miguelbernadi]

The Process function panics when the Do method returns a non-nil error. Some errors may be worth Panic'ing at that point, but others are not.

monkeylearn-go/pkg/monkeylearn/client.go

Line 38 in e8a4c00

if err != nil { log.Panic(err) }

Identify the sources of error in that case and explicitly handle sanely those situations that can be handled. Also document the tradeoffs clearly in the project documentation.

[miguelbernadi]

The returned error is supposed to be of type url.Error https://godoc.org/net/url#Error which includes methods to verify if it's a temporary error or a timeout. Let's decide what we should in each case.