Stuart/update documentation (#9)

* Updated documentation to assume docker image is being used

* Updated formatting of shell snippets

* Updated formatting of shell snippets

* Update README.md

* Update README.md

Author: nyalloc

example-02/README.md

@@ -18,7 +18,7 @@ Building the example
 
 ``` sh
 $ mkdir build && cd build
-$ cmake ../
+$ cmake ../ -DSYCL_ROOT=${SYCL_ROOT_DIR} -DCMAKE_CXX_COMPILER=${SYCL_ROOT_DIR}/bin/clang++
 $ make -j 8
 ```
 

exercise-01/README.md

@@ -23,7 +23,7 @@ Building the exercise
 
 ``` sh
 $ mkdir build && cd build
-$ cmake ../
+$ cmake ../ -DSYCL_ROOT=${SYCL_ROOT_DIR} -DCMAKE_CXX_COMPILER=${SYCL_ROOT_DIR}/bin/clang++
 $ make -j 8
 ```