WIP: Errno::ECHILD thrown from Process.waitpid
Let's untag one of specs and see what happens!
Merge pull request #731 from jstepien/tag-specs

Tag some language and Process specs
Errno::* are subclasses of SystemCallError
Add an Errno generator, move some code out of try
Merge remote-tracking branch 'origin/master' into errno-echild
Process#{wait,wait2,waitall}
fix Kernel#Array
fix Enumerator#with_index
Merge pull request #734 from kostya/enum3

fix Enumerator#with_index
Merge pull request #733 from kostya/array

fix Kernel#Array
Merge error_for_oserror and errno_for_oserror
Enumerable#chunk from rubinius
Merge pull request #736 from kostya/chunk

Enumerable#chunk from rubinius
Enumerable#slice_before from rubinius
replace with *args
Merge pull request #737 from kostya/slice_before

Enumerable#slice_before from rubinius
Minimise the try block in error_for_oserror
allocate does not accept any arguments
Merge pull request #732 from jstepien/errno-echild

Errno::ECHILD thrown from Process.waitpid, some Process methods