Access mode refactor

[nozavroni]

Check out how they are doing their access mode in this class:

https://github.com/binsoul/io-stream/blob/master/src/AccessMode.php

I don't want to require the use of an AccessMode class, but I want it to maybe be an option? Or maybe IO\Stream uses it internally? Think about it...

• [x] Write new CSVelte\IO\Resource class
  • [x] Add __invoke() method so that calling it as a function returns the underlying stream resource (it calls $this->getResource() Actually now it opens the resource if it isn't opened/connected and then returns the IO\Stream object.
  • [ ] Is it possible to implement __sleep() and __wakeup() on this thing?
  • [ ] What about __toString()? What would that do? My guess would be that either there isn't a meaningful way to convert it to a string, OR return string representation of underlying resource OR return URI (but this last one doesn't even come close to representing the entire stream resource as a string so I dont like #it)
  • [x] Figure out where stream_get_meta_data goes
• [ ] Unit testing - this is a surprisingly complex class. It is going to need a significant amount of unit testing in order to be considered safe to use.
  • [ ] Test uses of __invoke()
• [ ] Documentation
  • [ ] API Docs (thorough docblock comments)
  • [ ] RTD User's Guide documentation - add a section to the streams guide

[nozavroni]

The rest of this can wait until the next version.