updated changelog

CHANGELOG.md

 # vNext
-- More graphite functions
+- Text panel now accepts html (for links to other dashboards, etc) (Issue #236)
 - Fix for Text panel, now changes take effect directly (Issue #251)
 - Fix when adding functions without params that did not cause graph to update (Issue #267)
 - Graphite errors are now much easier to see and troubleshoot with the new inspector (Issue #265)
 - Use influxdb aliases to distinguish between multiple columns (Issue #283)
 - Correction to ms axis formater, now formats days correctly. (Issue #189)
 - Css fix for Firefox and using top menu dropdowns in panel fullscren / edit mode (Issue #106)
+- More graphite functions
 
 # 1.5.2 (2013-03-24)
 ### New Features and improvements
@@ -131,4 +132,4 @@ Thanks to everyone who contributed fixes and provided feedback :+1:
 
 # 1.0.0 (2013-01-19)
 
-First public release
\ No newline at end of file
+First public release