Always allow custom wildcards

Removed unnecessary restriction that custom wildcards are only possible when 'before' and 'after' are false/disabled.
This allows queries like:
Text LIKE '%This _s _ T%t%', when "This ?s ? T*t" was entered as search query, while 'before' and 'after' are true.
One or the other can be false, too
Merge pull request #112 from ravage84/always-wildcards

Always allow custom wildcards
Removed Behaviors->detach, replaced Behaviors->attach by Behaviors->load()

``BehaviorCollection::load()`` exists since CakePHP 2.0.0
https://github.com/cakephp/cakephp/blob/2.0.0/lib/Cake/Model/BehaviorCollection.php#L104
General DocBlock, comment and code cleanup of SearchableBehaviorTest
Fixed @license part order in all files

http://www.phpdoc.org/docs/latest/for-users/phpdoc/tags/license.html#syntax
General DocBlock, comment and code cleanup of fixtures
General DocBlock, comment and code cleanup of test suite
Removed unused variable in SearchableBehavior
General DocBlock, comment and code cleanup in PrgComponentTest
Replaced skipIf() with markTestSkipped()

http://api.cakephp.org/2.2/source-class-CakeTestCase.html#103-115
Partly reconstructed testSubQueryEmptyCondition()

The test was very similar to testSubQueryCondition().
In the past this test looked different:
https://github.com/CakeDC/search/commit/784a1ca12a4bc87c2c0cc3ba2b5cdd92b3b484de#diff-6dd7f6dbf96b52929673d36d7e558781R300

Somebody with more in depth knowledge should have a look.
Fixed one test and removed another that isn't necessary anymore since always allowing wildcards.
Merge pull request #113 from ravage84/total-cleanup2

Total cleanup v2
Fixes a missing word, see https://github.com/CakeDC/search/pull/115
Preliminary commit of the updated search plugin documentation
Working on improving the documentation
Refactoring the documentation
Working on the documentation
Working on the documentation
Working on the documentation