Small doc updates

Minor README fix
Updated doc comments to fix doc gen errors
Merge pull request #19 from splunk/docspass2

Small doc updates
Misc changed for Beta release

1. Upgraded to Json.Net release 11
2. Changed assembly version and file version to 0.8.0.0
3. Updated CHANGELOG.md for the release
Using assembly file version attribute in UserAgent

This is to avoid having version numbers in two places.
Merge pull request #21 from splunk/develop

Develop
Updated README for beta
Merge pull request #22 from splunk/docspass2

Updated README for beta
Merge branch 'develop' of https://github.com/splunk/splunk-sdk-csharp into develop
Merge remote-tracking branch 'origin/develop' into feature/ModularInputs
Minor code clean up; added more code comments