Semantic syntax highlighting

[jnm2]

I was going to start an issue about another syntax highlighting issue and realized I'm starting a bunch. The bigger picture is that it would be good to have Roslyn semantically highlighting everything so that there can be no inconsistencies to maintain, especially as new features get added to the language.

Hopefully putting the burden on Roslyn will solve these and future issues as well:

• [ ] #40 Syntax highlighting ignores / / style comments
• [ ] #42 C# keywords inside strings should not be highlighted
• [ ] Not all keywords are highlighted (public and static are two)
• [ ] The @ is not colored the same as the quotes in verbatim strings
• [ ] \" is incorrectly detected as an escape sequence and the string highlighting is inside out thereafter: @"Data Source=(LocalDb)\" + "v12.0"
• [ ] using is not properly colored for the statement version

[jnm2]

It this was tracking work that you still want to do, please feel free to reopen! Otherwise, cleaning up due to inactivity.