Report error to user if analysis is aborted prematurely

[mewmew]

As seen in #45, an analysis may be aborted before reaching the proper end of execution if binee runs into a scenario where it cannot continue analysis; such as an indirect call to an address for which no code is mapped or hooked.

To help users of binee assess the situation an error should be reported to the user, indicating that the analysis was aborted prior to completion.