Ignore files generated by agda-mode

I'm not sure when agda-mode started to generate these files, or if this
is a bug. Anyways, these can be safely ignored.

Author: ibbem

.gitignore

@@ -5,6 +5,9 @@
 *.#*
 .dir-locals.el
 
+# emacs' agda mode
+src/agda2-mode*
+
 # build
 src/cc
 src/Main