Added localisation strings for "Change username" feature
i18n(background): Backgrounds => "User Backgrounds" @lemoness
chore(i18n): update locales
fix(backgrounds): clearer wording wrt lim editions

Fixes https://github.com/HabitRPG/habitrpg/issues/3610
chore(i18n): update locales
Fix for issues #3573 - Correction for strange pixel on gems.
Merge pull request #228 from robeden/develop

Fix for issues #3573 - Correction for strange pixel on gems.
feat(summer): summer event
innText update of groups.json 2nd try

Trying again without incorporating username.
Merge pull request #230 from wc8/patch-1

innText update of groups.json 2nd try
Beastmaster: props -> congratulate (remove slang)

"give this user props" is an idiomatic phrase that non-native-English speakers could have problems with, especially since "prop" is also a noun that refers to an object. 

A player in the Tavern today said, _"Yeah! Beast Master Quest Complete! :D What about this 'give this user props!', am I going to get some cool gear or sth? :D"_  I had to disappoint him with the sad truth. :)
feat(crits): Make crit hits boost MP

Another nudge to make STR more attractive: critical hit on a To-Do multiplies MP gain.
fix(winter): add specialClass to winter 2013 items

Fixes https://github.com/HabitRPG/habitrpg/issues/3641

Removed "can own" text and replaced it with specialClass, so that Winter 2013 items grant class bonus.
fix(tests): add in freeRebirth

Really, I should fix this more systematically, but I think this should fix the tests for the moment, which is badly needed.
fix(tests): add in freeRebirth
"No Back Accessory" for base back - fixes #3640

Changes the text and notes for the base back gear from "No Helm" to "No Back Accessory".
Merge pull request #235 from Alys/patch-2

"No Back Accessory" for base back - fixes #3640
Merge pull request #233 from Alys/patch-1

Beastmaster: props -> congratulate (remove slang)
chore(i18n): update locales
add string to groups.json

step 1: https://github.com/HabitRPG/habitrpg/issues/3649 dataTool string