Handle NCDFE for odd envs like GAE that throw it for Unsafe.

Fixes #2304.
Open3.capture* only exist on 1.9+.
Reduce travis build times by only running on one JDK version.
[build] switch to released jnr-posix

[skip ci]
[Truffle] Basic new implementation of large hashes.
[Truffle] Fix ToFNode copy constructor.
[Truffle] Remove useless copy constructors in NilClassNodes.
Eclipse: Ignore more Eclipse-generated files.
rename spec files
Merge pull request #2322 from k77ch7/change_name_of_files_which_pass_rspec_regression_test_1215

change name of files which pass rspec regression test on master
[Truffle] Remove useless node copy constructors.

* A couple of them are actually incorrect.
[Truffle] Detect wrong copy constructors and strengthen the varargs VS fixed check.
Update to latest deps
Revert "[Truffle] Remove useless node copy constructors."

This reverts commit 391076d550df9dd8928a54331981f308c44dd257.
[Truffle] Fix bad copy constructors.
Revert "[Truffle] Remove useless copy constructors in NilClassNodes."

This reverts commit 476bd7f4c07c99e16d363312882e9376879090a2.
Move directed graph into external project
We don't need this to know it is a set
Load ourselves the default build properties in core/pom.rb.

* This allows Eclipse to generate a correct Constants.java.
Implement Enumerable#to_h from 2.1. Tests from MRI. Fixes #2315.