Add a .editorconfig to improve the formatting of the code on GitHub

[wilkinsona]

GitHub supports EditorConfig and looks for a .editorconfig file in the root of the repository. We can use it to, for example, configure the tab width to 4.

[wilkinsona]

It's branch-specific so I think we should add it to (at least) 1.4.x, 1.5.x, and master

[philwebb]

The .editorconfig we've added[1] breaks thing for me in IJ, I had to disable its support. The most obvious issue so far is that json is not using tabs and is not indented using 4 chars. Do we want to use tabs in json? And 4 chars?

[philwebb]

Let's try tweaking it to just .java files.

[vpavic]

This broke continuation indents in IntelliJ for me. Using continuation_indent_size (which appears to be a non-standard property) fixes the things:

diff --git a/.editorconfig b/.editorconfig
index 176815b35..26c1be094 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -3,7 +3,9 @@ root=true
 [*.java]
 indent_style = tab
 indent_size = 4
+continuation_indent_size = 8
 
 [*.xml]
 indent_style = tab
 indent_size = 4
+continuation_indent_size = 8

[snicoll]

Thanks @vpavic I've disabled the support in IJ on my side. Perhaps we should reconsider adding that file at all?

Ping team.

[philwebb]

I'd like to keep it if possible, lets try with those non-standard additions for a while. Long term the plan is still to try and unify the auto-formatting plugins.