Feat: Tokenize tool directives

[Schottkyc137]

Closes #179

Tokenize tool directives of the form

`identifier { arbitrary text }

In the current implementation status, this PR only tokenizes the tool directives. Any further processing is omitted for now. In the future, standard tool directives like the protect tool directive could be used for analysis

[kraigher]

Hi @Schottkyc137 I have some more time now after summer vacation so I will start to process your PRs. Sorry for the delay.

[kraigher]

The code looks good and I have no problem merging it. One follow up question I have is if tool directives always are a single line by standard definition? Or is parsing to the end of line just a heurestic you have assumed? Will encrypted IP just have a single line for the encrypted blob?

[Schottkyc137]

Hi @Schottkyc137 I have some more time now after summer vacation so I will start to process your PRs. Sorry for the delay.

Good to see you back, I hope you had a nice vacation!

The code looks good and I have no problem merging it. One follow up question I have is if tool directives always are a single line by standard definition? Or is parsing to the end of line just a heurestic you have assumed? Will encrypted IP just have a single line for the encrypted blob?

The standard (LRM 15.11) states that

A tool directive starts with a grave accent character and extends up to the end of the line.

I hope that this is how the encrypted IP will behave. The examples that I have seen in the issues weren't only occupying one line but this could just as well be a copy-and paste artifact somewhere. At the moment, I can't test this with Vivado but I will probably be able to do so later today or tomorrow. So if you want to, you can postpone merging until this is clear.