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
better tokenizer and fixed docstring
fixed merge of predicates
better tokenizing
reduced seach space for alpa
started on canonicalization
changed p/r tradeoff
fixing up docstrings
added working on sections
added working on sections
added working on init documentation
added working on init documentation
added working on init documentation
some fixes that arose from working with the servista data
refactored semiSupervisedSampling close #119