Limit Surface bounding error (idaholab#1217)

* limit surface error bound

* Closes idaholab#1216

* added new requirement

* considering the number of points, the error bound can be at maximum accurate to 1e-3

* fixed perturbation

Dump HistorySet MetaData into the correct output csv files (idaholab#987

)

* enable historyset to handle both scalar and vector meta data, and add check for NAN from code collections

* fix

* fix HistorySet

* fix reading vector meta data

* update tests

* add unit test for meta data load, print, reload

* fix

* modify test to test only the mechanics

ExternalXML in RAVEN Code Interface (idaholab#594)

* moved ExternalXML reader to xmlUtils

* found common replacement strategy for both ElementTree and InputTree

* RrR ExternalXML compatability and test

* documentation

* pylint file to open fix

* reviewer comment

2017 July Workshop version

Various updates including faster metadata

Open source approved