Close input Scanners after use.

git-svn-id: file:///Users/ghelmer/svn/projects/GradingHelper@30 d9e7442b-0272-427a-90c7-dca5c97caf01
Add support for securityPolicyFile element under the program element of the grading.xml file.
If the securityPolicyFile is set for a program, add the java.security.manager and java.security.policy
properties to the java command line arguments. Also add a grading.base property that provides
the root directory containing the grading files so it can be used inside the security policy file
to specify allowed pathnames.

git-svn-id: file:///Users/ghelmer/svn/projects/GradingHelper@31 d9e7442b-0272-427a-90c7-dca5c97caf01
Merge remote-tracking branch 'git-svn'