Change Fixnum to Integer (for Travis)

This is because Travis runs 32-bit vms.
Also add .pairs file.

Change-Id: I0800af65c3c3acdcea65c36c6b72f42054b89871
Merge remote-tracking branch 'origin/master' into staging

Change-Id: I366d17cb921cbf062ef4d36071bc8bb2c3a37bad