Mpxj

* Add Primavera Parent Resource ID as a specific resource attribute (Based on a contribution by Dave McKay).
* PMXML writer generates currency record (Based on a contribution by Dave McKay).
* PMXML writer defaults Activity PercentCompleteType to Duration (Based on a contribution by Dave McKay).
* PMXML writer records currency and parent attributes for Resource (Based on a contribution by Dave McKay).
* PMXML writer resource assignments include RateSource and ActualOvertimeUnits attributes(Based on a contribution by Dave McKay).
* MSPDI reader: gracefully handle invalid calendar exceptions..
* PMXML writer: gracefully handle missing data.
* Planner writer: gracefully handle missing data.

* Update universal project reader to support zip files.
* Update ruby to align error handling with universal project reader.

* Universal project reader.
* Avoid NPE when reading PMXML files.
* Fixed [Issue 297](https://sourceforge.net/p/mpxj/bugs/297): Missing extended attributes
* Fixed [Issue 300](https://sourceforge.net/p/mpxj/bugs/300): CrossProject field omission causes issues when importing to P6

* Updated to use POI 3.15.

* Avoid NPE when field type is unknown.
* Improve Ruby error reporting.
* Improve support for non-standard time formats in MPX files
* Improve support for MPP14 files with very large numbers of blank tasks

* When reading an XER file, treat FT_STATICTPYE user defined fields as text.