Centralize JSON parser choice in ZnUtils

[labordep]

This is now possible to load Zinc OAuth2 package directly from the package and to use it with the Pharo STONJSON parser.

• Unit test
• minor fixes
• adding .gittatribute file to manage End of file encoding between Windows and others OS

[labordep]

Hi @svenvc, sorry for adding the .gitattribute file but this is the only way for me to contribute without encoding problems from my Windows PC. Delete it after if you want.

[svenvc]

Hi,

This looks good to me, I will integrate it next week.

Thx,

Sven

[labordep]

Hi @svenvc, I'm using your OAuth2 (with user confirmation) stuff for desktop-app is this is working fine ! I have do a little fix (see my PR) but nothing important :)

[svenvc]

Thank you!