refextract: 'surname initial(s)' author recognition support.

• Author names with the surname before the initials are now recognised as part of an author group, only when they appear at the beginning of an author group and there is at least one standard ('initial(s) surname') author appearing after it.

• Made some minor changes to the author regex, and removed the unnecessary handling of 'ans' for incorrectly spelt 'and's.

• Added some more example reference lines to the 'test_reference_lines' list, which will at some point be included into the refextract_tests suite.