Update pointers and commands in readme

Author: mpkorstanje

CONTRIBUTING.md

@@ -177,8 +177,8 @@ To deprecate an item:
 
 ## Building the Project
 
-Please refer to [the readme](README.md#building-from-source) for the most common
-build commands.
+Please refer to [the readme](README.md#building-from-source) and [the documentation readme](documentation/README.md) for
+the most common build commands. 
 
 ### Build Parameters
 

documentation/README.md

@@ -18,7 +18,7 @@ This following Gradle command generates the HTML version of the User Guide as
 `build/docs/asciidoc/user-guide/index.html`.
 
 ```
-gradlew asciidoctor
+./gradlew asciidoctor
 ```
 
 On Linux operating systems, the `graphviz` package providing `/usr/bin/dot` must be
@@ -30,5 +30,5 @@ This following Gradle command generates the PDF version of the User Guide to
 `build/docs/asciidocPdf/user-guide/index.pdf`.
 
 ```
-gradlew asciidoctorPdf
+./gradlew asciidoctorPdf
 ```