Add "repeatCount" to allowed properties on default clip in animation files.  Clone default clip on animation cloning.
Clone animation target when cloning material parameters.
Non-public, separate property strings.

Requested by project owner.  Used same pattern for the value as seen in
original Animation.cpp.
Merge pull request #810 from germinator/master

Animation properties and cloning.
Merge pull request #817 from blackberry/master

Merge master to next