Implement a ArrayProperty class

[NickDraper]

This should be a templates class to accept doubles, ints and maybe strings (not if it causes extra trouble).

The property should parse string input seperating on commas to create the seperate elements. These then need to be cast and stored in an internal vector.

Once this is completed let Dickon know as he wnats to use this in his Rebin algorithm.

[NickDraper]

This issue was originally trac ticket 99