Add bin to gitignore

Because these files are mussing up my clean history, and I think they change every time I run make install.

License: MIT
Signed-off-by: Richard Littauer <richard.littauer@gmail.com>

.gitignore

@@ -10,3 +10,6 @@
 *~
 
 .ipfs
+bin/gx
+bin/gx*
+bin/tmp