Readme: remove old developer docs saying to run grunt before a PR

This is hard when we have many PRs open and often get left with a bunch of merge conflicts.

Author: Blendify

README.rst

@@ -257,7 +257,6 @@ This default task will do the following **very cool things that make it worth th
 4. It'll rebuild the sphinx docs anytime it notices a change to .rst, .html, .js
    or .css files.
 
-
 Before you create an issue
 --------------------------
 
@@ -269,15 +268,6 @@ way for me to ignore your request. RST unfortunately can spit out a lot of thing
 in a lot of ways. I don't have time to research your problem for you, but I do
 have time to fix the actual styling issue if you can replicate the problem for me.
 
-
-Before you send a Pull Request
-------------------------------
-
-When you're done with your edits, you can run ``grunt build`` to clean out the old
-files and rebuild a new distribution, compressing the css and cleaning out
-extraneous files. Please do this before you send in a PR.
-
-
 TODO
 ====