Promoted 'getUniquePath' method from AbstractFile to Content interface.
Refactored implementation of 'getUniquePath' in several implementing
classes. These changes in support of AUT-753.
Merge branch 'master' of https://github.com/sleuthkit/sleuthkit
Merge pull request #149 from tmciver-basis/master

In support of AUT-753
Made all three implementation of Content.getUniquePath be synchronized.
Merge branch 'master' of https://github.com/sleuthkit/sleuthkit
Merge pull request #150 from tmciver-basis/master

Made 'getUniquePath' synchronized.