Update README.md

The raw location for the sbt file has changed.
This fixes that so the installer `curl` command
works now.
Merge pull request #72 from JohnMurray/patch-1

Update README.md
Slightly more robust ivycp.
Update some versions.
0.13.5-M4 for dev sbt version.
Sacrificing some life to the test monster.
De-duplicated a bunch of test code.

Dear god people, come on. Are we programmers or what.
A bunch more deduplication.

Not being paid by the word people.
And more.

It would be hard to find a better example of the high
cost of test code (when such code is not properly managed.)
And lots more.

I think gzip could compress this stuff 96%.
The sea runs red with the blood of the redundant.

This is always how I picture things going whenever I'm not
willing to look too closely at a pull request.
I am a painter of tiny figurines.
sbt_rejecting.
Maybe people do get paid by the word.

And I'm missing out on the good opportunities.
Satan dines from my open skull.
Eliminating fragile dependencies on meaningless details.
Test compression.

That might have to do for now.
Execute tests under BATS_TMPDIR, not inside the repository.
Eliminate super-collision-oriented variabled named TMP.

Tried to eliminate the screwing around with $HOME, failed.
Reduced hardcoding of paths.