Added caching to type->shortname and shortname->type conversions.

[nvivo]

@Horusiath, @Aaronontheweb Added some caching to type resolvers.

Related to #28 (comment)

I'm not able to run the performance tests here for some reason. Both VS and build runtests fails to run the performance tests. Would like to see some numbers at least before merging this. Please let me know if this works.

[Horusiath]

This is not requirement, but an idea: GetShortAssemblyQualifiedName is actually used in 2 external places (TypeSerializer and ObjectSerializer). In both places this string is converted to a byte array immediately after. What we could do here, is to make this method return a byte array directly, avoiding string conversions in the future.

[nvivo]

@Horusiath I was looking into this. There is an issue with this optimization. For ObjectSerializer this idea works fine, but TypeSerializer has it's own way to serialize values directy to the stream. I tried replacing the StringSerializer for the ByteArraySerializer and the tests didn't pass. We would need 2 caches one for each format, or change something else to make them equal.

Another thing is that since GetShortAssemblyQualifiedName is recursive, caching itself helps a little resolving names the first time. Then again, we could add second cache, but increase memory usage. Not sure if there would be significant gains.

Using the cache should make the protocol at least as fast as it was before. Worst case, a dictionary + lock could be faster in some scenarios.

This is getting complicated... =) I believe it's better to merge this as it is and try to optimize this later.

[Danthar]

Is there anything that is preventing this PR from being merged ?

[nvivo]

Should I update this to netstandard or is there another solution in the works?