Fixed a bug with dynamicYaml's ability to find keys.

The yaml document would parse fine but due to a short circuit `||` operator certain valid keys could never be retrieved off a dynamic object.

E.g.:
```yml
---
SomeProperty: 3.0
```
would always return null when accessed due to the capitalized first character.

I fixed the bug, simplified the code involved (IMHO), and added unit tests for failing (and existing passing) cases.
I preserved the pre-existing behavious that allowed the first character of the key to be case in-sensitive. I think this behaviour is a little silly but I did not want to introduce a breaking change.
Separate IObjectDescriptor from IPropertyDescriptor to isolate accessors from metadata.
Merge pull request #95 from antmt/dynamic-key-bug

Fixed a bug with dynamicYaml's ability to find keys.
VS2013 support for Yaml Editor Extension
Merge pull request #99 from fantasticjamieburns/master

VS2013 support for Yaml Editor Extension
Merge remote-tracking branch 'origin/master'
Add unit test to verify that merge keys are correctly implemented.
Implement merge keys.
Update version number.
Fix unit tests that was mistakenly reverted.
Fix NullReferenceException in case of duplicate anchor.