pull request test for updating lang file

Task # 104 : Can create an invoice from several orders

Fixed dictionary form

Add a new column in llx_c_tva

Qual: Add PHPUnit tests

inside dolibarr code (Really dont know why it fails with 1900. It
looks like a year 2000 bug). Let's try with 1915 and 1916

Fix: use company name if lastname and firstname not exists

Qual: Add indexes

Unit tests are back ok (when tag is @6 or @=, yearoffset
is not zero but must not be applied when replacing yyyy). 
Compatibility with 3.2 is also restored.

Qual: Add a lot of phpunit tests to validate all get_next_value()
cases.

Minor fix

New: Support unique field for extrafields

When creating or modifying an entry, id param was lost
Also, missing </form> added