Remove broken JSPerf link

Fixes #692

docs/moment/04-displaying/01-format.md

@@ -430,10 +430,6 @@ moment().format('[today] dddd'); // 'today Sunday'
 
 For a breakdown of a few different date formatting tokens across different locales, see [this chart of date formatting tokens.](https://docs.google.com/spreadsheet/ccc?key=0AtgZluze7WMJdDBOLUZfSFIzenIwOHNjaWZoeGFqbWc&hl=en_US#gid=0)
 
-#### Formatting speed
-
-To compare Moment.js formatting speed against other libraries, check out [this comparison against other libraries](https://jsperf.com/date-formatting/49).
-
 #### Other tokens
 
 If you are more comfortable working with strftime instead of LDML-like parsing tokens, you can use Ben Oakes' plugin. [benjaminoakes/moment-strftime](https://github.com/benjaminoakes/moment-strftime).