Removing the binary documentation files.

They are burdensome to maintain.
Resolves #108

The markdown version of the Developer's Guide will continue to be maintained.

Author: leekelleher

README.md

@@ -49,8 +49,6 @@ To clone it locally click the "Clone in Windows" button above or run the followi
 
 For details on how to use the Doc Type Grid Editor package, please refer to our [Developers Guide](docs/developers-guide.md) documentation.
 
-A PDF download is also available: [Doc Type Grid Editor - Developers Guide v1.0.pdf](docs/Doc-Type-Grid-Editor--Developers-Guide-v1.0.pdf)
-
 ---
 
 ## Known Issues