Remove an outdated module

Closes #512
Add a note about required build tools and packages

Closes #518
Don't run cargo as root during `make install`

This rejiggers the dependencies for `make install` to only copy files into the
destination, never assemble anything. This adds a hard requirement that `make`
is executed before `make install`.

Closes #519
Don't deadlock when a dep has no libs
Update libssh2-static-sys to build on msys2
Mention the name of a package in a custom build failure

Closes #530
auto merge of #516 : alexcrichton/cargo/issue-512, r=brson

Closes #512
auto merge of #527 : alexcrichton/cargo/build-issues, r=brson

Related issues in the commits.
auto merge of #529 : alexcrichton/cargo/msys2-build, r=brson
auto merge of #532 : alexcrichton/cargo/issue-530, r=brson

Closes #530
auto merge of #528 : alexcrichton/cargo/deadlock, r=brson
fix sample code to do with color-rs. Renamed HSV to Hsv and RGB to Rgb so that it compiles and works
Clarify why bins have Cargo.lock but libs don't

Closes #525
auto merge of #536 : superlogical/cargo/master, r=alexcrichton

So that it compiles and works
auto merge of #534 : alexcrichton/cargo/issue-525, r=brson

Closes #525 

r? @wycats
Add a NUM_JOBS env var to builds

Closes #539
Fix some minor typos
auto merge of #543 : alexcrichton/cargo/doc-fixes, r=alexcrichton
Switch the location of the docopt repo
auto merge of #546 : alexcrichton/cargo/docopt, r=huonw