don't export png's and compilers to the final users

Though they are still available to the devs, as they are just
`export-ignore`d in the .gitattributes. I've done a little bit of
research, and this attribute prevents the files from being archived by
git. So, I'm assuming that package control fetches archives of the
packages, and not the actual ones. But I haven't found any documentation
on packagecontrol.io stating that. I quickly browsed its source code
on GitHub, and couldn't really find anything. So, I'm going to contact
@jfcherng, who showed me this trick on FileManager.

.gitattributes

@@ -0,0 +1,3 @@
+docs/ export-ignore
+resources/*.png export-ignore
+resources/*.py export-ignore

resources/convertresources.py

@@ -1,8 +1,5 @@
 """ A small script to convert the images into base64 data """
 
-# FIXME: ignore this script and the original images in .gitignore so that it pushes to
-#        the GitHub repository but not package control
-
 from base64 import b64encode
 
 with open('404.png', 'rb') as png, open('404.base64', 'wb') as base64: