Updates

[RalucaNicola]

• I added snippets for WaterSymbol3DLayer and added the patterns property on FillSymbol3Dlayer.
• Fixed a missing coma in the edges snippet.
• Added all new symbols (including 2D ones) to the readme file.
• Converted 2D symbol snippets from using spaces to using tabs. @ekenes let me know if you see smth wrong with this. I wanted to switch to tabs so that users get the number of spaces that they set in their editor's config files (and also to have the same style for all the snippets).
• Updated the changelog with the new changes
• Updated the getAPI snippet with the newest versions.

[RalucaNicola]

@kellyhutchins I will merge this tomorrow, maybe you can have a quick glance just to see if you notice anything weird.