Here's a failing and a passing test for #1378
Here's an implementation of $1000/wk for plurals

If someone changes from a plural to a singular they'll bring their big
tips with them.
Teach js about new max for plurals
Update fake_data for new tip max distinction
Failing test re: taking big tips to singular
Make sure tip distribution handles large tips
Constrain number changes when user has big tips
Here's a couple more update_number tests
Clean up logic around updating number

We had an update_number method on Participant but weren't actually using
to update the number.
Propagate number-changing error out to user
Merge pull request #2433 from gittip/raise-limit-for-plurals

raise limit for plurals