Version bump to 1.2.1, contains minor bugfixes and language changes

Added a player validity check, should fix minor IsMuted lua error

Switched ErrorNoHaltWithStack for MsgC and chat.AddText

v1.2.0 First (truly) stable release, the addon has been completely revamped and improved, with new features for ease of use, quality of life and preferences.

- New interface available for all gamemodes with the concommand "chatping" (TTT still has a special tab in the helpmenu)
- English and Spanish languages
- Unlimited and cross-server aliases
- Player muting
- Self-pinging
- Visual pings
- Alias-only and visual-only modes
- New sounds, with a selector and tester for each sound
- Errors are a lot less annoying
- Custom sounds are easier to install and test

https://github.com/actuallyNothing/chatping/

-Code refactoring, hook renaming and file restructuring
Changes are visible in GitHub: https://github.com/actuallyNothing/chatping

-Removed Loopback option
-Replaced alphanumerical distinction with two new cvars: 'chatping_alias_enable' and 'chatping_alias'
-Alias enable a player to set a secondary keyword to trigger the pingsound
-Revamped Derma UI for TTT helpmenu to make it easier to read and understand

-Fixed typos in cvars
-Added support for non-case-sensitive matching
-Added support for TTT helpmenu (F1)

-Changed scope of variables from global to local

-Commenting

-Unique hook ID
-"chatping_sound" help text correction