Added initial .editorconfig file.

.editorconfig

+###############################################################################
+# Unity Project - A Test Framework for C
+# .editorconfig - F. Zahn 2019
+###############################################################################
+
+# This is the topmost .editorconfig file
+root = true
+
+# Settings that apply to all languages / files
+[*]
+charset = utf-8
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.txt]
+trim_trailing_whitespace = false
+
+[*.rb]
+indent_size = 2
+
+[*.yml]
+indent_size = 2