Update predicates.py

1. Spelling on docstring for sameSevenCharStartPredicate, "characters"
2. same"N"CharStartPredicate results in substantial redundancy. Consider deprecating in favor of: initials
3. common"N"Gram -> ngrams

Questions: How should spaces be regarded within a 'field' for the ngrams function?

Issues:
- nearIntegersPredicate(field) disregards negative integers indicated by "-" (other than -1 in the case of 0)

Consider also:

def ingrams(field, n):
    """produces an iterator over ngrams generated from a sequence of items
    
    see: http://nltk.googlecode.com/svn/trunk/doc/api/nltk.util-module.html#ingrams
    """
    ...
Update predicates.py

Updated initials() :param n to default to None, meaning if no integer value n is provided, the entire field will be returned.

Fixed broken change to nearIntegersPredicate
reverted wholeFieldPredicate body re: @fgregg
Caugh edge cause for initials of n=0 v. n=None
Merge branch 'patch-1' of git://github.com/mekarpeles/dedupe into mekarpeles-patch-1
make n arg in initial non-optional