* logger for d2audio & d2map
* logger for d2ui e.t.c
* d2inventory now passes on error messages
* no more importing log in d2core
* implemented #925
* added logger to part of d2networking & fixed "need to be changed" comments
* fixed lints
* fixed errors
Co-authored-by: M. Sz <mszeptuch@protonmail.com>
* fixed lint errors in button.go
* fixed lint errors in checkbox.go
* Removed d2ui singleton, fixed nearly all lint errors
- Changed `UI` struct to `UIManager`, removed singleton
- UI element provider functions are now methods of the UI Manager
- Screens now use the UI manager to create UI elements
- game panels in d2player now use the UI Manager to create UI elements
- Only the UI manager knows about "widgets"; calls to `d2ui.AddWidget` in Screen instances have been removed
* changed ui element provider methods from `Create` to `New`
