Release v1.0.1564

Release version v1.0.1564

Metacello new
    baseline: 'GToolkitForPharo9';
    repository: 'github://feenkcom/gtoolkit:v1.0.1564/src';
    load

All commits (including upstream repositories) since last build:
https://github.com/feenkcom/gt4pharo/commit/0fc89a by John Brant
[feenkcom/gtoolkit#4319] self type for advice stylers