A few tweaks to description of players

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extra : rebase_source : 6cb29b69e2984aef4d303c7e4d3296fa231cd5af
Rework description of timed item associations

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extra : rebase_source : 36cff473da8b681c960610c8cc5a61a32f7668dd
Add issue about timing functions on groups

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extra : rebase_source : 5e01e2e1d29d359074f405dcf307896139f38b15
Add description to Timing.easing that some types of timing functions may not be supported