Fixed visibility of external teachers application link. Closes #365
Merge pull request #366 from samfcmc/feature/link_external_teachers

Fixed visibility of external teachers application link. Closes #365
Bug fix: Closes #367
- when a degree had not previous enrolment periods it wasn't possible to
create new enrolment periods for that degree
- the access validation was being made inside the cycle which resulted
in the above behavior and it is not necessary to validate that in every
iteration
import file from interface with some validations for the fields that are readed from the excel
class refactor
creating people only with the mandatory fields
instead of lots of ifs we are now using field importers to load a given field from a row
Internationalization of the fields readed and the columns names; Refactor of the FieldImporters to a container; Rules for importing the file
automatically validating all the contacts for the imported persons
template for batch import