Remove `:nls_characterset` and `:nls_nchar_characterset`
from optionals NLS parameters

Oracle does not support change these parameters at session level.
Merge pull request #266 from yahonda/nls_support

Remove `:nls_characterset` and `:nls_nchar_characterset` from NLS optional parameters
Added note about Tomcat Usage

Tomcat requires to set the accessToUnderlyingConnectionAllowed to true in the context.xml file. Otherwise, weird errors pop up (undefined method 'meta_data' for nil:NilClass)
Merge pull request #267 from Xylakant/patch-1

Added note about JNDI Usage with tomcat
Add a testcase for issue #134
Issue #134 :returning_id column should be of type Column.
Merge pull request #274 from yahonda/returning_id_master

Address :returning_id column should be of type Column
Supports table_name prefix/suffix for add_foreign_key

Closes reenhanced/oracle-enhanced#1

LGTM given by: @codenamev

Squashed commit of the following:

commit b1c0fedfca69cde2d20ea362ea738afd422e516e
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Dec 11 11:16:39 2012 -0500

    typo

commit 6f776e4589a2a0e6873d1d624428db29bfae904d
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Dec 11 11:07:25 2012 -0500

    Supports table_name_suffix for add_foreign key

commit db3c2655a7717905443348f576e4a278942ce903
Author: Nicholas Hance <nhance@reenhanced.com>
Date:   Tue Dec 11 10:44:34 2012 -0500

    Support table prefix for add_foreign_key