Simplify addition of unit test cases that use reference files

[palemieux]

Adding a use case based on a reference file requires modifying:

• build.xml
• build.properties
• MXFFragmentBuilderTest.java

... and generating reference files requires copying reference registers to both:

• regxmllib/src/test\resources/reference-registers
• input/xml-registers

Suggest:

• assuming that all files in sample-files should be turned into reference-files
• use reference-registers for both reference file generation and unit test checking

[palemieux]

use reference-registers for both reference file generation and unit test checking

Addressed by c75de63

[palemieux]

assuming that all files in sample-files should be turned into reference-files

This will not work in all cases since some sample files are used for other purposes.

6bbb8c1 removes the need to tweak build.properties