This allows to add new kinds of keys that need more data without making
KeyValue's footprint bigger for common keys.
This changes the [_symbol] field into [_payload], which holds the same
as the previous field for more common keys but can hold bigger objects
for keys of the new "Complex" kind.
This also adds a complex key: String keys with a symbol different than
the outputted string.
Unit tests are added as the Java language is not helpful in making
robust code.
Put new example in Examples section; put all overview material at start; use "modmap" for the modmap tag but "mapping" for the various subtags; set out each subtag separately; stop illustrating example mappings as complete modmap.
* Post-edit on Metadata
① Tell reader exactly what to type to disable locale_extra_keys, as with prev. bullet
② Values should be quoted
③ Rephrase one passive
* locale_extra_keys obviates 2nd example under modmap
* Modmap: Where to put it; cancelling built-in mods (#665)
* Correct per Julow: not only Euro layouts
* Post-edit: Doesn't depend on "built-in" layout
* P-vs-L: Change "That is to say", sentence is not a restatement
* Discussion with Julow: Swipe graphic to HTML; at most one modmap
* Swipes: Center tables
This adds the new 'anticircle' attribute to layouts '<key>' elements
that configure the key to send when doing a anti-clockwise circle
gesture on it.
Labels are drawn the same way as indication.
Updated docs.
