newdata=extractor(data,cn,valinf,valsup)

extracts from DATA, all the lines whose the CNth column
has values included between valinf and valsup

DATA = matrix N X M
CN = Column Number (target)
VALINF = Low limit
VALSUP = High limit
NEWDATA = Extracted Matrix

Example:
a =

1 2 3
4 5 6
1 7 8
1 4 9
4 7 2
9 6 5

extract data with third column included between 0 and 5:
>> extractor(a,3,0,5)

ans =

1 2 3
4 7 2
9 6 5

extract data with first column exactly equal to 4:
>> extractor(a,1,4,4)

ans =

4 5 6
4 7 2