Extended the test slightly and implemented the 'return true/false' component mentioned in the issue.

addKeyboards parameter property:  'language' -> 'languages'.

Sets init param 'attachType' to 'auto' for all devices.

[Mac]: Prevent Keyman processing command keys

Cherry picked a few small changes from "mac compatibility" branch to fix bug whereby command keys were sometimes causing characters to be output.

name/id mismatch in MergeKeyboardInfo

Move KMBM variable out of KV member in keyboards to match compiler behaviour

Fixup attachType for web debugger in Keyman Developer

Addresses the recent iOS image asset requirement change.

Removes the 'free' set of asset images and attaches the newly required 'marketing' 1024x1024 icon.  Addresses #371.

Refactor longpress logic so key text is not confused with key code

`String.fromCharCode()` has a limitation to Unicode characters in the BMP. Change to `String.kmwFromCharCode()` to handle entire Unicode range.

Also clarified how default key codepoints are processed.

KeyboardHarness changes:
- Change text area font on keyboard change
- Added U_10481 to test longpress keyboard.
- Remove test tchad keyboard

Update comments explaning how control codes U_0000 to U_001F and U_0080 to U_009F are suppressed.

Also updated longpress test keyboard to test control codes.

* Fix accessing AltGr shift layer
* Fix AltGr OSK layer to display as "Alt Ctrl"
* Fix how Unicode control characters are filtered out, so U_00A0 can be displayed

Rework of KMW keyboard registration + default keyboard selection.

Mobile default-layer shifting regression fix

Corrects KMW auto-attach behavior.

A tchad keyboard has a diacritic rule that converts `=` (U_003D) into a combining macron (U_0304).
A longpress on `»` (U_00BB) was inadvertently triggering the diacritic rule, and outputting the macron.

The longpress code in KMEA and KMW needs to be refactored so they dont confuse key text (U_00BB is decimal 187) with underlying keyCodes (`=` is keyCode 187).

- fix KMW executePopupKey so key code is dictionary lookup instead of parsing the keyID.
- clean up JS call to executePopupKey since it only uses the keyID

Fixup regression for debug-mode keyboards using touch keys (hexadecimal format error)

Refactors KeymanWeb sample & test pages.