Fix whitespace issues

Summary:
This change applies the following awk script to the _includes folder:

• { sub(/\r$/,""); print } to convert CR+LF into LF
• { sub(/[ \t]+$/, ""); print } to remove extraneous spaces at EOL

Test Plan: no-op

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1158