Make VerifyRequestMessage more readable
Refactoring

Reorganize namespaces and folder structures.
Change scope of static fields in the Input/Output helper classes.
Fix comment spelling errors.
Make fields in helper class NMACommand read-only
Change return type of internal helper method
Make field in helper class Parameter read-only
Rename _usageChangedEventHandlers and make it read-only
Make _errorCode field in NMAException read-only
Make _key field in NMAKey read-only
Make _source field in NMAResponse read-only
Make _callsRemaining and _timeUntilReset fields in NMAUsageChangedEventArgs read-only
Make RandomGenerator field in RandomNumberGenerator read-only
Refactor NMAResponse

Make the 'Source' field read-only
Make the 'GetAttribute' method more readable
Fix exception parameter order.
Improve 'ToQueryString' algorithm in 'KeyRing'
Rename variables in 'NMAClient' to avoid hiding properties
Improve exception messages in 'NMAKey'
Remove redundant Imports statement
Switch Input/Output filenames around to match the containing types
Improve 'GetAttribute' algorithm
Code cleanup

Organize imports.
Remove redundant identifiers.