Add message to RS docs about application vs. library packaging.

RenderScript kernel language used in this script. Currently, 1 is the only valid value.</li>

<li>A pragma declaration (<code>#pragma rs java_package_name(com.example.app)</code>) that

declares the package name of the Java classes reflected from this script.</li>

declares the package name of the Java classes reflected from this script.

Note that your .rs file must be part of your application package, and not in a

library project.</li>

<li>Some number of invokable functions. An invokable function is a single-threaded RenderScript

function that you can call from your Java code with arbitrary arguments. These are often useful for