Make pymssql cursor.callproc() translate SP errors to a PEP 249 exception.

Fixes #61.
tox.ini: Install a working IPython on py26 env.
Merge pull request #230 from pymssql/fix-tox-py26-ipython

tox.ini: Install a working IPython on py26 env.
setup.py: Make clean command acually remove Cython-generated files.
Merge pull request #231 from pymssql/fix-clean-setup.py-command

setup.py: Make clean command acually remove Cython-generated files.
Add ChangeLog entry.
Merge pull request #224 from pymssql/61-handling-of-sp-errors

Make pymssql cursor.callproc() translate SP errors to a PEP 249 exceptio...
docs: Fix _mssql connect() arguments.
Merge pull request #232 from pymssql/update-_mssql-connect-params-docs

docs: Fix _mssql connect() arguments.
Fix tds_version _mssql connection property value for TDS 7.2.

Refs 32584060 and a8f58fa1.
Merge branch 'master' into fix_tds_version_7.x_return_values

Conflicts:
	ChangeLog
docs: Small updates.
Merge pull request #234 from pymssql/docs-updates

docs: Small updates.
Fix some docstrings and comments typos.
Merge pull request #236 from pymssql/docstrings-typos

Fix some docstrings and comments typos.
tests: Expand Stored Procedure invocation tests.

- Show it's also possible to call SPs with output parameters by using
  the helper pymssql.putput class.
- Show it's possible to fetch results of queries performed by SPs
  both from _mssql and pymssql.
_mssql: Check negative bound when converting from Python ints->TDS INTN.
Merge pull request #238 from pymssql/add-negative-intn-limit-check

_mssql: Check negative bound when converting from Python ints->TDS INTN.
pymssql: Made handling of integer SP params more robust.
Made test compatible with Python 3.