TST Import sqlalchemy on Travis.

DOC add docstrings to read sql

ENH read_sql connects via Connection, Engine, file path, or :memory: string

CLN Separate legacy code into new file, and fallback so that all old tests pass.
TST to use sqlachemy syntax in tests

CLN sql into classes, legacy passes

FIX few engine vs con calls

CLN pep8 cleanup
add postgres support for pandas.io.sql.get_schema
Merge remote-tracking branch 'origin/master' into sql

Conflicts:
	ci/requirements-2.6.txt
	ci/requirements-2.7.txt
	ci/requirements-2.7_LOCALE.txt
	ci/requirements-3.2.txt
	ci/requirements-3.3.txt
	pandas/io/sql.py
	pandas/io/tests/test_sql.py
WIP: cleaup of sql io module - imported correct SQLALCHEMY type, delete redundant PandasSQLWithCon

TODO: renamed _engine_read_table, need to think of a better name.
TODO: clean up get_conneciton function
ENH: cleanup of SQL io

TODO: check that legacy mode works
TODO: run tests
correctly enabled coerce_float option
Cleanup and bug-fixing mainly on legacy mode sql.
IMPORTANT - changed legacy to require connection rather than cursor. This is still not yet finalized.
TODO: tests and doc
Added Test coverage for basic functionality using in-memory SQLite database
Simplified API by automatically distinguishing between engine and connection. Added warnings
Initial draft of doc updates
minor doc updates
Added tests and reduced code repetition. Updated Docs. Added test coverage for legacy names
Documentation updates, more tests