Add Time.at
Fix array clone frozen object error
fix Array#rindex
More specs of Time.{at,eql?,tv_sec,usec) pass
Add File#zero?
Add Kernel#chop
Merge pull request #793 from jstepien/time-at

Add Time.at
Merge pull request #794 from sideshowcoder/fix_array_clone

Fix array clone frozen object error
Merge pull request #795 from kostya/rindex

fix Array#rindex
Merge pull request #798 from sideshowcoder/add_kernel_chop

Add Kernel#chop
style change
Merge branch 'pr/796'
random style fixes
Merge branch 'master' into type-specialized-attrs