markdown cleanup, installation.txt link added (#478)

README.md

@@ -1,13 +1,8 @@
-PRMan for Blender
-===============
+# PRMan for Blender
 
-<a href="https://github.com/bsavery/PRMan-for-Blender/releases"'><H2>Get Latest Release</H2></a>
+Blender render addon for Pixar's RenderMan 21.0 and beyond. To use, install RenderMan, (free from [renderman.pixar.com](http://renderman.pixar.com/view/non-commercial-renderman)), download [the latest release](https://github.com/bsavery/PRMan-for-Blender/releases) and put it in the addons folder for Blender. See the [installation.txt](installation.txt) file for detailed instructions.
 
-Blender render addon for Pixar's RenderMan 21.0 and beyond.  To use, install RenderMan, 
-(free from http://renderman.pixar.com/view/non-commercial-renderman), 
-download this project and put it in the addons folder for Blender.  See the installation.txt file for detailed instructions.
-
-For support visit the renderman forums https://renderman.pixar.com/forum/forumdisplay.php?s=&forumid=166
+For support visit the [RenderMan forums](https://renderman.pixar.com/forum/forumdisplay.php?s=&forumid=166).
 
 Many thanks to Matt Ebb for the initial 3delight/Blender plugin this is forked from.
-Also thanks to contributors to this release: rgordon, aek, jdent02, jdbener
+Also thanks to contributors to this release: rgordon, aek, jdent02, jdbener