AssemblyWalkAttribute.cs
* New class to manage walking the loaded assemblies looking for classes, interfaces, or attributes
* Decorate manager classes with this attribute to define how the class should register other types

Bootstrapper.cs
* Add call to AssemblyWalkAttribute.Walk from the Start method.

BoundVariable.cs
* Clear the cache if you set the bound variable

Opcode.cs
* Switch casting method to avoid casting error.

SafeFunctionBase.cs, FunctionBase.cs, FunctionManager.cs,
SafeBindingBase.cs, Binding.cs, BindingManager.cs, kOSProcessor.cs
* Create new classes in kOS.Safe to serve as safe base classes.
* Move as much logic into kOS.Safe as possible.

kOS.Safe.csproj, kOS.csproj
* Reference new classes and remove old references.

Convert existing Addons to the new attribute system

AddonManager.cs
* New manager class for all addons.
* Receives the register calls of AssemblyWalkAttribute
* Contains a static list of all kOSAddonAttributes and associated types
* Instantiated by the processor as a member of kOS.SharedObjects

kOSAddonAttribute.cs
* New attribute class for decorating kOS Addon classes.
* Important to remember that the class must inherit from kOS.Suffixed.Addon as well (defined by AddonManager)

kOS.csproj
* Add references to new classes.

AddonList.cs
* Rework AddonList to create suffixes based on Addons in AddonManager
* Add new suffixes for HASADDON and AVAILABLE to allow scripts to check if the addon is installed and if it is available

kOSProcessor.cs, SharedObjects.cs
* Add references to the new AddonManager

TelnetMainServer.cs
* use `GetValue` instead of the string index to return permission
setting values in order to stop exceptions when loading and the key is
not present.

AssemblyWalkAttribute.cs
* Fix ToString to be more useful by identifying its class, and then the
criteria.
* Add a could comments
* Fix attempting to force Interface/Inherited conditions to accept an
attribute condition as well.
* Add more detail to error messages.
* Remove logging output for every class that does not satisfy
Interface/Inheritance conditions.

KOSNomenclature.cs
* Implement AssemblyWalkAttribute.
* Move logic from assembly based methods into stand alone single type
methods.

Bootstrapper.cs
* Remove call to KOSNomenclature PopulateMapping

Addon Readme.md
* Add some documentation for how to implement a new Addon.

Addon Readme.md
* Clarify assembly/project separation.
* Reference the parameter of the KOSNomenclature attribute

AssemblyWalkAttribute.cs
* Log assembly location when it cannot be loaded
* Create a couple of constant string format fields.
* Remove uneeded zero parameter check in CheckMethodParameters

Binding.cs
* Remove Update method that was hiding the inherited Update method.