Better organized .gitignore

.gitignore

+# generated files
 *.o
-*~
+*.os
+*.so
 *.a
+*.gem
+*.pyc
 *.class
-*.so
-jni/com*.h
-src/test_suite
-lib/hush
+libhammer.pc
+build/
 examples/dns
 examples/base64
 examples/base64_sem1
 examples/base64_sem2
-TAGS
-*.swp
-*.swo
+jni/com*.h
+src/test_suite
+
+# coverage and profiling stuff
+*.gcov
+*.gcda
+*.gcno
+gmon.out
+
+# editor leftovers
+*~
+*.sw?
 \#*
+
+# misc
+lib/hush
+TAGS
 docs/milestone2.dot.pdf
 *.dot.pdf
 Session.vim
-*.gcov
 cscope.out
-build/
-libhammer.pc
 .sconsign.dblite
-*.os
-*.pyc
-*.gem