Respect `$akHandle` in RatingHelper

Respect `$akHandle` parameter in
`RatingHelper::getAverageChildRating()`

Allows for using rating helper with custom attributes
Add Default `$akHandle` 'rating' to `RatingHelper`

- Add default `$akHandle = rating` to
  `RatingHelper::getAverageChildRating()
- Add default `$akHandle = rating` to
  `RatingHelper::outputAverageChildRating()
Fix Attempting to Display Blank Errors

Fix attempting to display blank errors in single pages

- This is particularly apparent with the newer `Controller::$error`
  property.
Fix Customize Theme in Greek Yogurt

Fix customize theme in greek yogurt

- Change `p-font` to `paragraph_font`
- Change font to shorthand
Move `config/file_types.php` above Pkg `on_start`

Move `config/file_types.php above `startup/packages.php` to allow
`Package::on_start()` to override file types with
`FileTypeList::define()`
Fix Date Nav Add/Edit Block Error

Fix date nav add/edit block error

- `value` was `undefined` but compared in conditional
- Check for `undefined` before comparing
Correct Conditional Typo

Correct conditional typo
Prevent null result when no matches found

In some instances a null value is returned when there are no matches, even when the original string should be shown (e.g. http://www.concrete5.org/developers/bugs/5-6-1-2/file-manager-search-shows-no-title-if-keyword-is-in-attribute-ra/)
Fix Legacy URL Parse

Fix legacy url parse

- Use `preg_replace` to only get `-/` to avoid dashes further down
Upgrade SimplePie to 1.3.1

Upgrade SimplePie library to version 1.3.1

- Addresses issue with PHP >= 5.3 `DOMElement::getLineNo()`
Revert Attribute Value null parameter

Revert attribute value null parameter

commit: 1e052dd97bd6d946ddb9c816db040c63b8acdb97
Merge pull request #1163 from mkly/revert_attribute_null_parameters

Revert Attribute Value null parameter
attribute tweaks
Merge branch 'master' of github.com:concrete5/concrete5
Merge pull request #1144 from mkly/check_for_rating_attribute_handle

Respect `$akHandle` in RatingHelper
Merge pull request #1149 from mkly/fix_empty_system_error_display

Fix Attempting to Display Blank Errors
Merge pull request #1150 from mkly/fix_customize_theme_greek_yogurt

Fix Customize Theme in Greek Yogurt
Merge pull request #1152 from mkly/fix_date_nav_block_not_saving

Fix Date Nav Add/Edit Block Error
Merge pull request #1151 from mkly/move_config_file_types_above_on_start

Move `config/file_types.php` above Pkg `on_start`
Merge branch 'patch-10' of github.com:melat0nin/concrete5 into merge_prevent_highlight_search_return_null