Mailster - Email Newsletter Plugin for WordPress 4.1.11

- added: implement installation checks and enhance default settings handling
- added: link to documentation for capabilities settings page
- added: new capability to delete campaigns with appropriate roles and help text
- added: new helpdesk links to the settings page
- refactored: improve notification template fallback and error handling
- refactored: improve SMTP configuration type casting
- refactored: improve wp_mail filter argument handling
- fixed: correct parent block references for condition blocks
- updated: enhance import functionality and UI interactions
- packages updates

fixed: improve capabilities and permissions system
updated Dependencies and Package Versions
chore: update commit message guidelines
updated: improve form block error handling
updated: refactor homepage block edit and inspector controls

- fixed: missing capability to delete campaigns in some case
- fixed: missing key in array function
- added: new capabilities `delete_private_newsletters`, `delete_published_newsletters`
- improved: alignment of elements in the automation inspector
- improved: use `ToggleGroupControl` on update custom field action for checkboxes
- package upgrades