Remove database requirement

[marip8]

As of e8aecb612f815dd4a06a78a6affe2f0d53f4f0c6, it seems like a MySQL database is required to run the tool path planner application. Ideally we should be able to interact with the tool path planners without needing to go through the database set up process. In the short term we ought to:

• [ ] Document that the MySQL database set up is no longer optional in order to use the planner application
• [ ] Create an Rviz panel for loading a mesh, generating a tool path, and saving the path to a file

[drchrislewis]

I like that there is a database option. Many clients want it this way. However, it would be nice to simply be able to save tool path plans to files. I'd rather require someone to install an unused database than have two different tools to maintain.

[marip8]

I think the keyword is option. I agree that it's a nice feature, and I'm not proposing we get rid of it. However, I think this package would be more usable if there were a tool path planning GUI that worked out-of-the-box without forcing the user to go through so much additional and unnecessary set up. We already have the low level widgets, we just need to create a simple panel or two that lets people use the planners directly

[drchrislewis]

After further thought, I believe we should can the database altogether. The only reason we used it in the first place is that it was a requirement for a project. However we don't use many, if any, database features. We could just as easily implemented a simple directory structure and that would have been much simpler to use. I vote to drop the database altogether. The tool is really nice to use for all sorts of reasons. However, its not well thought out. We should do a real re-design of the interface. A number of missing capabilities should also be added. For example, for grinding and sanding one needs to generate paths that don't go over the boundary you define, so they should always remain 1/2 tool radius from the drawn boundary. The job structure is also flawed. I just want a list of tool paths associated with a part. Then a job should be a sequence of tool paths. We should add the edge path generation too. This tool has huge potential, and should be done well. Let's organize a design.