sub menus didn't get checked for being active.

Based off the method in ```Menu.php``` I've updated ```Nav``` so it will check if sub menus are active or not.
Improved check for active child items

Updated to avoid full tree traversal.
Also noticed ```activateItems``` didn't do anything so that's been fixed.
Update CHANGELOG.md
Added asElapsedTime function
Typo in asElapsedTime description
Call Yii::t everytime instead of passing a template variable
Typo
asElapsedTime can now take DateInterval as parameter
asElapsedTime style improvements
asElapsedTime can now take a DateInterval string as a parameter
Added support for inverted intervals (future time) and unit tests
Removed debug code, changed doc
Added $action param.
Modified example in DataReader usage comment to reference a DB Command function which accepts a SQL string argument.
Reformat code te be PSR-2 compatible
Merge pull request #2764 from SonicGD/go-for-psr-2

Reformat code to be PSR-2 compatible
Fixed test break.
Fixed typo in FilterValidator for skipping array values.
Merge pull request #2767 from ZhandosKz/filter_validator_skip_on_array

Fixed typo in FilterValidator for skipping array values.
typo fix in gii.md