[Developer] Re-implement Convert-to-character command in web text editor

[Developer] Track deadkeys more reliably in debugger

[Developer] Support CSS, JS and JSON formats in text editor

[Developer] Project window needs to support untitled projects

[Developer] Support printing from ACE text editor

[Developer] Tidy up row selection in web editor

[Developer] Remove old popup menu and attach command event for new menu for text editor

[Developer] Manage focus correctly for setting breakpoints and more

[Developer] Remove Alt+letter/digit and function key bindings from editor

[Developer] Support Escape key in text editor to clear error highlight

[Developer] Support context menu in text editor

[Developer] Remove Alt+letter/digit and function key bindings from editor as they conflict with environment bindings

[Developer] Support context menu in text editor (some commands not yet implemented; this is infrastructure)

[Developer] Restore support for 'reformat xml document' in ACE editor

[Android] Remove ad-hoc distribution of keyboards via keyman:// protocol

* Clean up unnecessary `KMKey_` keys
* Update MainActivity to only download ad-hoc KMP packages.

[Android] Validate keyboard ID when downloading keyboard from Keyman cloud

Cherry-pick of #1121

[Android] Ensure keyboards list has an entry

Cherrypick #1112 to master

There are some crash reports coming from `KeyboardPickerActivity.java` because the keyboards list is null (file access error). When the app tries to display the installed keyboards list, this results in the crash.

`getKeyboardsList()` already checks the existence of the `keyboards_list.dat` file, so some of that code is also redundant.

[Android] Change default keyboard from european2 to sil_euro_latin

[Windows] Windows Delphi Community Edition support

[Developer] Fixup debugger integration with ACE-based editor