Fix issue with dependencies, among other selector issues

[joshwcomeau]

Related Issue: closes #251

Summary: Shoot, so yesterday I merged some code that memoized our redux selectors. Kinda late in that PR I changed it so that selectors had a new format: selector(state, props: {arg1, arg2}) (instead of selector(state, arg1, arg2, ...)). This is how reselect wants it to be formatted, since it can easily do a shallow-compare on the props object and use that for memoization (I'm guessing, at least? I didn't dig into this).

Unfortunately, I didn't do a very good job checking that everything still worked. Part of this was after merging master, but some of it was just my own negligence :/ I kinda thought Flow would catch anything I missed, but it's not smart enough to unpack saga select statements.

This PR fixes a number of issues around that, including:

• Missing dependency pane
• Dependencies installing to Guppy instead of the target project
• Build/test/eject tasks not able to run

[melanieseltzer]

Would this error be related to this PR? (throws after installing a new project) Looks like it can't find project.dependencies which I feel like is prob related since you said dependencies pane is gone. Didn't want to open a new issue if it's related...

[superhawk610]

@melanieseltzer I can confirm I also get that error on Linux.

[joshwcomeau]

@melanieseltzer yep, that's related. This was a nasty oversight on my part, broke a bunch of stuff D: