Add GetSource() method (Requires CefStringVisitor implementation) - performs GetSource() in an async fashion, so doesn't just return a value
Implement GetSource and GetText in an Async fashion - uses TaskStringVisitor as a wrapper around a TaskCompletionSource
Add GetSource() Sync method and WinForms example usage
Fix CefSharp.csproj - Accidentally got updated during cherry pick
Add GetText() sync method
Fix minor indentation issue (formatting)
Add license disclaimer
Merge pull request #373 from amaitland/feature/get-source

Add GetSource() and GetText() including their XxxAsync() counterparts