Update the JobManager to correctly report the right exception and cleanup the JobManager state

[masesdevelopers]

The latest version reports an incorrect Exception, the internal Exception becomes an ArgumentNullException. Anyway the engine becomes unusable: seems the problem is related to the throw clause moved within the catch which avoids to call the EndOperation handler and consequently does not cleanup the internal state.

Originally posted by @masesdevelopers in masesgroup/NuReflector#17 (comment)

[masesdevelopers]

The following

JCOReflector/src/engine/SharedClasses.cs

Line 163 in c9debce

public static ErrorReportingType ErrorReporting { get; set; }

becomes a bool property and

JCOReflector/src/engine/SharedClasses.cs

Line 1286 in c9debce

internal static void EndOperation(EndOperationEventArgs arg)

will be invoked in any case.
Plus will be added a new method Clean to reset the state if something goes wrong.