Add an EditorConfig file

I didn't (and couldn't) actually test this in any way, but hopefully this makes
it easier to edit awesome's source without vim.

Thanks to Daniel Hahler for telling me about this.

Signed-off-by: Uli Schlachter <psychon@znc.in>

.editorconfig

@@ -0,0 +1,26 @@
+# See http://editorconfig.org
+
+# Don't search for other .editconfig files
+root = true
+
+[*]
+
+# Unix-style newlines
+end_of_line = lf
+
+# There a newline at the end of the file
+insert_final_newline = true
+
+# Trailing whitespaces, no one needs them
+trim_trailing_whitespace = true
+
+# Why would anyone use anything else?
+charset = utf-8
+
+# This is just what we use, sorry if you disagree
+indent_style = space
+indent_size = 4
+
+# In a Makefile, the tab is significant and not "just" whitespace
+[Makefile]
+indent_style = tab