Integrate li3_quality in Scrutinizer checks.

[mariuswilms]

It would be great to integrate the syntax checks into the scrutinizer CI. The following document details how this can be achieved:

https://scrutinizer-ci.com/docs/tools/custom-commands/

The syntax command will then need to be able to work with single files (instead of whole libraries). See #10. In general the command should not use the Libraries class to find its files.

[bayleedev]

I believe it can be ran on single files.