Added importer file and test_importer file.
First Definitions of exporter
Add function write
imported the importer in the spectraplotpy lib ( __init__.py)
defined importer class and aviv importer subclass.
defined test for aviv importer and importer.
Stylish modifications for Oscar....
Merge https://github.com/odarbelaeze/spectraplotpy

Conflicts:
	spectraplotpy/__init__.py
More addition
Merge branch 'master' of https://github.com/odarbelaeze/spectraplotpy
Included dataset class in import class.
Added number of data to dataset.
Stylish things for Oscar.....
Exporter passing the linter.
Merge pull request #2 from lidiabressan/master

Importer class impelemeted for Aviv files
Merge pull request #3 from mboufatah/master

I implement first lines for exporter
Merge pull request #4 from ariamania/master

added the operation of a spectrum