node conf: supply resource_limit.conf examples

Bug 1133936 - Provide some usable canned resource_limits profiles
https://bugzilla.redhat.com/show_bug.cgi?id=1133936
Not sure what you mean about tuning for m3.large... the diff is comments:

    $ diff -u resource_limits.conf{,.small*}
    --- resource_limits.conf	2014-08-27 14:36:41.501701597 -0400
    +++ resource_limits.conf.small.m3.xlarge	2014-08-27 14:14:22.829244564 -0400
    -# Default Profile
    +# Small Profile

I can make those changes, you would definitely know better than me what an m3.xlarge will support. It might be a little odd changing this default midstream but max_active_gears=100 has always seemed a bit high and I expect it's the first thing customers know to change.