Added has copyright and has license attribute to delta objects

[Pratikrocks]

In this PR I added a the option to add the attribute has_license and has_copyright to the delta objects.
When either of the new file of the old file has a copyright or an license this attributes will be set to true,by default it is False
`
class Delta(object):
"""
A tuple reflecting a comparison of two files -- each of which is a File
object -- and the 'factors' (e.g., 'added', 'modified' etc.) and related
'score' that characterize that comparison.
"""
def init(self, score=0, new_file=None, old_file=None):
self.new_file = new_file if new_file else None
self.old_file = old_file if old_file else None
self.has_license = False
self.has_copyright = False
self.factors = []
self.score = score
self.status = ''

def add_license(self) :
    self.has_license = True

def add_copyright(self):
    self.has_copyright = True    

`

This PR is meant to solve issue of #109

[Pratikrocks]

@MaJuRG kindly review this

[steven-esser]

Why do we need these again?

[Pratikrocks]

@MaJuRG I provided it as attributes of every delta objects,as we can just check these booleans for determining weather the respective deltas has a license or copyright(either new or old file)
Depending on these booleans we can actually use the license Expression Library

[steven-esser]

Do we really need separate functions to simply change a field value?

[Pratikrocks]

@MaJuRG ,no actually it can be modified a bit and made to change the values in place,But I thaught creating a function for it wold be a better approach to it.

[Pratikrocks]

@MaJuRG Should I change it?

[steven-esser]

Yes. if all the function does is change a value, there is no need for it. We can add a function later if there is more complex operations to be done.

Also I question the need for these field anyway. Is there an issue regarding this or...?

[Pratikrocks]

Yes I think the issue of #109 is meant for it i.g

[steven-esser]

Ok then these fields are fine.

[Pratikrocks]

@MaJuRG do I need to make any changes further in this , as I think it suffices the requirements of the issues #109

[steven-esser]

Closing due to stagnation.