Packaging fixes.
Free trampoline from fiber stacks when allocated
Small cleanup for method with same functionality
Remove unused method from heap dump
Improve naming for integer conversion methods
Ensure to run return checks when NULL is returned

Fixes #2712
Cleanup unused function from JIT
Add spec for comparable with Range and no <=> method defined
Fix building a Range with comparable but no <=> defined

Fixes #2681
Add spec for rb_cDir
Add rb_cDir to C-API

Fixes #2651
Remove now unneeded instance variable from JIT visitor
Fixed rubinius metagem description.
Updated CI specs to RubySpec 47a1fc63.
Updated MSpec source to 439b4fa1.
Fixed Thread#priority, #priority=.

Since setting the Thread priority is already a no-op and Thread
priorities are essentially meaningless, we simply make it an
attribute. This also fixes a segfault that occurred because the
priority of a #join'd thread could be retrieved.
Fail if gem unpack fails.
Removed obsolete deviates block.
Return method name from Module#define_method.
Fixed Module#define_method spec failing on 2.1.