Update ignore for repo

.gitignore

@@ -1,2 +1,27 @@
 # never push ~ files
-*~
+*~
+
+# Ignore all
+*
+
+# Unignore all with extensions
+!*.*
+
+# Unignore all dirs
+!*/
+
+# Ignore emacs autosave~ and #modified# files
+*~
+**/*~
+**/\#*
+
+# Ignore main files
+**/*main.c
+
+# Ignore object files and libraries
+*.o
+*.ko
+
+# ignore _putchar.c and a.out
+**/_putchar.c
+**/a.out