autoload library directories

The vendor directory is managed by composer.  It's ignored by git and should not be [polluted](https://getcomposer.org/doc/faqs/should-i-commit-the-dependencies-in-my-vendor-directory.md) with non-managed directories.  So, I've added `library` folders for both Admin and Catalog.  They can be used for core ZC code as well as required 3rd-party code, such as Aura - which I've included.  Additionally, local code can also live there, i.e. `Texdc\Admin\MyFancyWidget` in `admin/library/texdc/my-fancy-widget` - if not managed by composer.

The autoload config has been moved to `admin/includes/config/config.autoload.php` so that it can be managed independently and overridden easily.  There are 2 new directory constants, `DIR_ADMIN_LIBRARY` and `DIR_CATALOG_LIBRARY`.  I can update the documentation on how to use and override these config files, when necessary.

Lastly, I believe that the `zcDashboardWidgetBase` class was inadvertently left out of #95.  It's renamed to `ZenCart\Admin\DashboardWidget\AbstractWidget`.

Thanks again for adding namespaces and autoloading :100: .  This is a great start to refining and modernizing ZC code!
<a href='#crh-start'></a><a href='#crh-data-%7B%22processed%22%3A%20%5B%22https%3A//github.com/zencart/zc-v1-series/pull/97%23issuecomment-48861020%22%2C%20%22https%3A//github.com/zencart/zc-v1-series/pull/97%23issuecomment-48861218%22%2C%20%22https%3A//github.com/zencart/zc-v1-series/pull/97%23issuecomment-48861255%22%5D%2C%20%22comments%22%3A%20%7B%22General%20Comment%22%3A%20%7B%22html_url%22%3A%20%22https%3A//github.com/zencart/zc-v1-series/pull/97%23issuecomment-48861020%22%2C%20%22comments%22%3A%20%5B%7B%22body%22%3A%20%22%3A-1%3A%20%5Cr%5CnThis%20PR%20refactors%20all%20kinds%20of%20things%20unrelated%20to%20Aura%2C%20and%20even%20unrelated%20to%20rewriting%20DashboardWidgets%20to%20your%20new%20%60library%60%20folder.%5Cr%5Cn%5Cr%5CnAs%20discussed%20previously%2C%20please%20keep%20your%20commits%20isolated%20to%20their%20purpose.%20%20Wholescale%20rewrites%20of%20unrelated%20code%20or%20changes%20unnecessary%20to%20the%20specific%20topic%20at%20hand%20will%20not%20be%20accepted%20in%20the%20same%20PR.%5Cr%5Cn%5Cr%5Cneg%3A%20your%20style%20preference%20of%20%60defined%28%27IS_ADMIN_FLAG%27%29%20%7C%7C%20die%28%27Illegal%20Access%27%29%3B%60%20instead%20of%20an%20%60if%60%20statement%20is%20only%20a%20style%20preference%20%28sure%2C%20%2Ayou%2A%20might%20call%20it%20an%20optimization%2C%20but%20it%27s%20still%20just%20a%20style%20preference%29.%20Same%20with%20your%20love%20of%20%60__DIR__%60.%20Do%20it%20in%20a%20separate%20PR.%20Don%27t%20clutter%20feature%20changes%20with%20style%20changes.%22%2C%20%22created_at%22%3A%20%222014-07-14T02%3A45%3A46Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/404472%3F%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/drbyte%22%7D%7D%2C%20%7B%22body%22%3A%20%22I%20don%27t%20like%20big%2C%20messy%20PRs%20either%2C%20but%20there%27s%20not%20much%20extraneous%20here.%20%20It%27s%20all%20related%20to%20reorganizing%20things%20into%20proper%20directories.%20%20There%20are%20more%20little%20changes%20than%20I%20like%2C%20too%2C%20but%20they%20were%20made%20during%20debugging%20to%20help%20me%20understand%20the%20code%20and%20were%20over-looked%20in%20the%20commit.%20%20Please%20indicate%20the%20specific%20changes%20you%20wish%20to%20be%20reverted%20and%20why%20and%20I%27ll%20do%20what%20I%20can%20to%20clean%20things%20up.%22%2C%20%22created_at%22%3A%20%222014-07-14T02%3A51%3A44Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/1590605%3F%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/texdc%22%7D%7D%2C%20%7B%22body%22%3A%20%22%60defined%28%27FOO%27%29%20%7C%7C%20define%28%27FOO%27%2C%20%27bar%27%29%3B%60%20is%20standard%20syntax%20for%20checking%20constants.%20%20It%27s%20used%20across%20multiple%20projects.%22%2C%20%22created_at%22%3A%20%222014-07-14T02%3A53%3A06Z%22%2C%20%22user%22%3A%20%7B%22avatar_url%22%3A%20%22https%3A//avatars.githubusercontent.com/u/1590605%3F%22%2C%20%22html_url%22%3A%20%22https%3A//github.com/texdc%22%7D%7D%5D%2C%20%22title%22%3A%20%22General%20Comment%22%7D%7D%7D'></a>
<a href='https://www.codereviewhub.com/'><img src='http://www.codereviewhub.com/site/github-bar.png' height=40></a>
- [ ] <a href='#crh-comment-General Comment'></a> <img src='http://www.codereviewhub.com/site/github-remaining.png' height=16 width=60>&nbsp;<b><a href='https://github.com/zencart/zc-v1-series/pull/97#issuecomment-48861020'>General Comment</a></b>
- <a href='https://github.com/drbyte'><img border=0 src='https://avatars.githubusercontent.com/u/404472?size=16' height=16 width=16'></a> :-1:
This PR refactors all kinds of things unrelated to Aura, and even unrelated to rewriting DashboardWidgets to your new `library` folder.
As discussed previously, please keep your commits isolated to their purpose.  Wholescale rewrites of unrelated code or changes unnecessary to the specific topic at hand will not be accepted in the same PR.
eg: your style preference of `defined('IS_ADMIN_FLAG') || die('Illegal Access');` instead of an `if` statement is only a style preference (sure, *you* might call it an optimization, but it's still just a style preference). Same with your love of `__DIR__`. Do it in a separate PR. Don't clutter feature changes with style changes.
- <a href='https://github.com/texdc'><img border=0 src='https://avatars.githubusercontent.com/u/1590605?size=16' height=16 width=16'></a> I don't like big, messy PRs either, but there's not much extraneous here.  It's all related to reorganizing things into proper directories.  There are more little changes than I like, too, but they were made during debugging to help me understand the code and were over-looked in the commit.  Please indicate the specific changes you wish to be reverted and why and I'll do what I can to clean things up.
- <a href='https://github.com/texdc'><img border=0 src='https://avatars.githubusercontent.com/u/1590605?size=16' height=16 width=16'></a> `defined('FOO') || define('FOO', 'bar');` is standard syntax for checking constants.  It's used across multiple projects.


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<a href='#crh-end'></a>
Local "configure.php" files are not always full copies of the real "configure.php" file.

For example enabling debug mode for authorize.net requires adding only one additional constant. With the original code one could add this single line of code to the local "configure.php".