Repaired SolutionUserObject read logic; added ability to read xdr and xda
(closes #3355)
Added legacy read capability
(refs #3355)
Merge pull request #3477 from aeslaughter/xda-3355

Repaired SolutionUserObject read logic
Merge commit '5190e3a6b90a70cb79c96d37f26877b499ace4c4'