PROTON-249: Use a source file list when compiling java sources to avoid hitting command line length limits

* changed UseJava's add_jar pass a source file list to javac instead of many individual files on the command line
* added function add_jar_from_filelist which behaves like CMake-builtin add_jar but accepts a file contain a list of files
  (used to compile Java output of Swig)
* added ProtonUseJavaSourceFileList to extract a list of Java source files from one or more directories

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1451242 13f79535-47bb-0310-9956-ffa450edef68