Deduplicate dependencies

[lqd]

Making polonius build a tiny bit faster (from scratch). There are still some duplicate crates (e.g. 3 regex-syntax) for now.

grep "name = " Cargo.lock | awk '{ print $3 }' | sort | uniq -c | grep -v "1 \""
Before:

2 "atty"
2 "bitflags"
2 "proc-macro2"
2 "quote"
2 "rand"
2 "regex"
3 "regex-syntax"
2 "strsim"
2 "syn"
2 "winapi"

After:

2 "atty"
2 "error-chain"
2 "rand"
2 "rand_core"
2 "regex"
3 "regex-syntax"
2 "strsim"
2 "winapi"

For the others, and especially the triple regex-syntax, I'll consult with the dependency de-duplication resident expert @Eijebong :)

---

Also, note that this updates the lockfile to include the polonius-engine 0.6.1 release, which I think was missing from #89.

r? @nikomatsakis

[lqd]

I've consulted with the aforementioned "dependency whisperer" (❤️) and most of those duplicates will be removed when we update to larlpop 0.16. However, blindly doing so apparently makes parsing tests fail so I'll investigate, update the parser and redo the dedupe later.

At this later time, updating assert_cli and ascii_canvas, will remove all but one duplicate. Updating ascii_canvas will however require merging lalrpop/ascii-canvas#1 and cutting a release prior to that.

[Eijebong]

You'll also need to update term in lalrpop and get a release there to avoid duping term here :p

[lqd]

Pushed a couple commits:

• Updated lalrpopto 0.16 (which itself also builds faster)
• Updated assert_cli to 0.6
• Removed an unused crate (histo).

The number of duplicate crates has gone down as expected:

2 "rand_core"
2 "winapi"