fbc namespace

[stellaprins]

• fix fbc namepace programmatically (if fbc is mentioned in the SED-ML document) like was done for the missing sbml namespace.
• check whether test suite example 01186 (missing fbc namespace) is processed correctly now (no namespace errors)
• check whether test suite example 00001 (no fbc namespaces) is still processed correctly

fbc namespace was added manually here.

❗I've discovered that unlike xlmns:sbml (which does not work when it goes at the end) xlmns:fbc cannot be added added as first entry in the sedML attribute of the SED-ML file. xlmns:fbc works as last entry (I did not systematically try all positions).

PR #86