Added a .gitattributes to configure how files are handled in git.

This is required for the integration tests in particular to ensure the line endings of the uncompressed files are not normalized.

.gitattributes

@@ -0,0 +1,20 @@
+# automatically handle text files
+* text=auto
+
+# text files
+*.md text
+*.txt text
+
+# source code files
+*.rs text
+*.c text
+
+# configuration files
+*.yml text
+*.toml text
+
+# compressed files
+*.gz binary
+
+# no end-of-line normalization should take place for integration test text files
+tests/*.txt -text