DOC: update DF.as_matrix and DF.values.  Closes gh7413
DOC: Add how to calculate month-start to cookbook

Related: #7449
Merge pull request #7417 from clham/7413

DOC: update df.as_matrix and df.values.  Closes gh7413
FIX integer column names for older sqlalchemy version GH6340, GH7330
Merge pull request #7456 from jorisvandenbossche/sql-fix7330

FIX integer column names for older sqlalchemy version GH6340, GH7330
BLD: use sqlalchemy 0.7.1 in 2.6 build (GH6340)
Merge pull request #7455 from shoyer/month-start-cookbook

DOC: Add how to calculate month-start to cookbook
Merge pull request #7022 from jreback/sqlalchemy

BLD: use sqlalchemy 0.7.1 in 2.6 build (GH6340)
ENH/API: offsets now accepts datetime64