Updated Changelog (markdown)

Changelog.md

@@ -15,7 +15,7 @@ Older versions are at the bottom of this page.
 
 * Introducing data-only exercises (the user submits only data which are validated by custom judge).
 * Improving Smart-Fill feature in test configuration form.
-* Gravatar optimizations -- user may disable/enable own gravatar and configure whether gravatars are visible to hir in general
+* Gravatar optimizations — user may disable/enable own gravatar and configure whether gravatars are visible to hir in general
 * Results table in Group Detail page is sortable by name and by total points now.
 * User may delete own submission comments.
 * Performance optimization of various SQL queries, functions, and visualization.
@@ -49,7 +49,7 @@ Older versions are at the bottom of this page.
 
 ## 28.3.2018
 
-* Group page redesign -- splitted into two pages (info and detail), cleaner design and much better performance
+* Group page redesign — splitted into two pages (info and detail), cleaner design and much better performance
 * Assignments can restrict the set of runtime environments (as a subset of the RTEs of the exercise)
 * Pre-submit files validation with automated environment selection and entry point (bootstrap file) selection
 * Entry point selection also added to extra files in the exercise config form