RBAC: Item and Assignment optimized save approach
RBAC: DbManager code style fixes
RBAC: DbManager code style fixes
cache tests refactoring cherry picked from redis branch
doc fix in caching classes
changed cache test to wait more than expirytime

change is to avoid random test failure on race condition.
fixes #203 #231
Merge pull request #230 from creocoder/rbac-db-manager-code-style

RBAC: DbManager code style
moved classes from framework -> yii
fixed db exception according to signature change
"YiiRequirementChecker" has been created as blank.
Method "YiiRequirementChecker::check()" has been implemented.
Method "YiiRequirementChecker::check()" has been refactored to be used in method chain.
Methods "YiiRequirementChecker::getResults()" and "YiiRequirementChecker::render()" have been added.
Test case "YiiRequirementCheckerTest::testCheckEval()" has been added.
better testing: time()-function-mock

as discussed in #203
https://github.com/yiisoft/yii2/issues/203#issuecomment-17759631
"YiiRequirementChecker::check()" has been updated to be able to collect different requirements set in the chained call.
mocking time in test only usefull when using time() once

https://github.com/yiisoft/yii2/commit/e2513de6c6207fa37894a944e10b8cd420ac6804#commitcomment-3192244
added newline to end of header and body blocks in View

issue #237
"YiiRequirementChecker::render()" has been implemented, console view has been created.
Web view for "YiiRequirementChecker" has been created.
Check helper methods have been added to "YiiRequirementChecker".