v0.7 wip

[mcollina]

• rename the term context into solution, as it's more clear Rename contexts to solutions everywhere #31.
• move from " to '.
• rename join() to search().
• introduce filtering Negation in Joins #27 in search() and get()
• introduce a 'limit' and 'offset' option in search() and get().
• callback to avoid deferred open enhanced levelgraph constructor with callback for when DB is ready #46.
• saucelabs testing

Closes #45.

[coveralls]

Changes Unknown when pulling 444754b on v0.7-wip into * on master*.

[coveralls]

Changes Unknown when pulling 6af24a3 on v0.7-wip into * on master*.

[mcollina]

@elf-pavlik, v0.7-wip is feature complete. It is a 'big' release. Could you please give it a spin and check if there are bugs?

I would love to give some polish to JoinStream and SortJoinStream, but time is up and I think it's better to release this.

[elf-pavlik]

congratulations for taking it to 0.7 👏

what do you think about adding deprecation warning to join(), or you want to keep this alias for good?

[mcollina]

You are right. I need to add a deprecation warning. Should I just use
console.warn?

[elf-pavlik]

I think console.warn() should do it for now!

If we need something more sophisticated we can look how other libraries do it. Ember.js fore example uses Ember.deprecate(): https://github.com/emberjs/ember.js/blob/master/packages/ember-debug/lib/main.js#L94
I can try searching in other libraries how they go about deprecating stuff...