[fix] Use the autolimit config parameter, as specified in the documentation. Fix #9
[mod] Remove unused imports
[enh] Use the Ipython system to handle config.

This allow configuration parameters to be inspected directly in
IPython using the %magic
[fix] Retain config set in profile
[enh] Document the parameters in the config

This way they can be seen with %config
[enh] Define the configuration directly on the Magic

As documented on https://github.com/ipython/ipython/issues/4206
Had to rename SQLMagics to SqlMagic to keep compability with current config.
[mod] Move execute back into SqlMagic

Made more sense than passing self twice.
Also test the magic directly using Ipython facilities
[test] Added a test for the autolimit parameter
[enh] Add an option to hide the traceback on SQL Programming Error

Default to False
Configurable via
%config SqlMagic.short_errors = True
(or the config file)
Going to remove plots from dataframes after all
Pie charts working
guesser for plot and pie passing tests
.plot() and .pie() working
Refactored tests
bar charts working
Documentation for v0.2.3
Merge pull request #11 from olethanh/use_ipython_config

Use ipython configuration system
Merge pull request #12 from olethanh/short_error_option

Short error option
make short_error default to TRUE
update docs
Added key access for result sets