Deploy -sources JARs to Maven repository (rebased onto dev_4_4)



This is the same as gh-225 but rebased onto dev_4_4.

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For a number of reasons, it is very useful to have these sources JARs
deployed. For example, in Eclipse, you can right-click on a Maven JAR
dependency and choose Maven > Download Sources, and it will then
automatically download the sources JAR and link them for debugging.