Add .gitattributes file.

Mark Python source files as "diff=python" to show the correct function
names, and mark various types of binary files as binary to avoid
attempting to diff/merge them.

Author: Benjamin Moody

.gitattributes

@@ -0,0 +1,14 @@
+*.py        diff=python
+
+*.anI       binary
+*.atr       binary
+*.d[0-9]    binary
+*.dat       binary
+*.edf       binary
+*.gz        binary
+*.mat       binary
+*.qrs       binary
+*.wabp      binary
+*.wav       binary
+*.wqrs      binary
+*.xyz       binary