Bug 10178 - Typos in plugins for 006 and 008 in MARC21

Bug 10178 - Typos in plugins for 006 and 008 in MARC21

Well, not only typos. There is also a NEW update for
006/8 Music on April 2013. And 3 missing values in 006.

Revised descriptions and labels, source LOC page.
Strings spell checked.

To test:
1) Apply the patch
2) Test that MARC21 006 and 008 value builders works
properly.

Small string changes.

Signed-off-by: Nicole C. Engard <nengard@bywatersolutions.com>
All tests pass

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
XML changes only, passes all tests.
Contains string changes, so should go into 3.14.