Update .gitignore

.gitignore

@@ -1,3 +1,4 @@
+# Temporary files
 *~
 *.swp
 *.o
@@ -7,10 +8,15 @@
 *.trs
 .deps
 .libs
+.DS_Store
+
+# Emacs
 GPATH
 GRTAGS
 GSYMS
 GTAGS
+
+# Generated by Autotools
 INSTALL
 Makefile
 Makefile.in
@@ -27,20 +33,25 @@ Makefile.in
 /missing
 /libmodbus.pc
 /stamp-h1
-/*.sublime-*
-/.vscode
 src/modbus-version.h
 src/win32/modbus.dll.manifest
+tests/unit-test.h
+
+/*.sublime-*
+/.vscode
+
+# Binary
 tests/bandwidth-client
 tests/bandwidth-server-many-up
 tests/bandwidth-server-one
 tests/random-test-client
 tests/random-test-server
 tests/unit-test-client
-tests/unit-test.h
 tests/unit-test-server
 tests/version
 tests/stamp-h2
+
+# Documentation
 doc/*.html
 doc/*.3
 doc/*.7