Did find and replace in TextMate.
```
find: (?:( \*)( ))?Copyright (?:\(c\) )?(\d{4})\b.+Facebook[\s\S]+(?:this source tree|the same directory)\.$
replace: $1$2Copyright (c) $3-present, Facebook, Inc.\n$1\n$1$2This source code is licensed under the MIT license found in the\n$1$2LICENSE file in the root directory of this source tree.
```
* Add back caught error and other checks to 'lowPriorityWarning'
**what is the change?:**
This change makes 'lowPriorityWarning' an exact copy of 'warning.js' from
e66ba20ad5/packages/fbjs/src/__forks__/warning.js
where before we had skipped some checks from that module.
- Adds an error which we catch, in order to let people find the error and resulting stack trace when using devtools with 'pause on caught errors' checked.
- Adds check that 'format' argument is passed
**why make this change?:**
- To maintain a closer fork to 'warning.js'
- To allow easier debugging using 'pause on caught errors'
- To validate inputs to 'lowPriorityWarning'
**test plan:**
`yarn test`
**issue:**
* Update 'print-warnings' script to include 'lowPriorityWarning' output
**what is the change?:**
We print the logs from 'lowPriorityWarning' as well as 'warning' from the 'print-warnings' script.
NOTE: This PR is branching off of https://github.com/facebook/react/pull/9754
**why make this change?:**
We want to use the same process of white/blacklisting warnings with 'lowPriorityWarning' that we do with 'warning'.
**test plan:**
This is not super easy to test unless we are doing a sync with FB afaik. I plan on running a sync in the next few days, or next week at latest, for the sake of not landing big things on a Friday. That will be the actual test of this.
**issue:**
https://github.com/facebook/react/issues/9398
Sophie Alpert