Checkboxes lost it's status if error occurred (e.g. invalid handle) when adding a new page type, now checkboxes are able to remains checked after error.
Normalize description of view_page_in_sitemap key

The description of the view_page_in_sitemap defined in version_562.php
and the one defined in permissions.xml should be the same.
Simplify translatable string
Fix mysql Exception Shown on Page Type Add

Fix mysql exception show on attempted duplicate page type handle
addition.

- Check for existing page type by handle and return error if found
Merge pull request #1303 from mlocati/patch-1

Simplify translatable string
Revert HTML Helper Inheritance

Reverty HTML Helper Inheritance

HeaderOutputObject causes chicken and egg situation with inheritance.
Final solution would need to be more involved.
Merge pull request #1306 from mkly/revert_fix_html_helper_core_inheritance

Revert HTML Helper Inheritance
Remove Variable Variables

Remove Variable Variables

Difficult to understand and servers no actual purpose here.
Fix type PermissionKey::add()

Fix type PermissionKey::add()

- Change `$$pkHasCustomClass` to `$pkHasCustomClass`
Revert 981cc42 allow null in getDirectoryContents

Revert 981cc42 allowing null parameter in
`Environment::getDirectoryContents()` as type juggling of interface
feels like it will encourage bad habits that cannot be taken back later.

Commit 981cc429e282a379e8b4930cbc8fffaf89f07752
Format contains string commit

Format contains string commit for concrete5 coding standards

Commit 90a7e73f8f13f7c3aa0e9e8718e88e71f6f5b9de
Merge branch 'fix/page-type-add/checkbox-states-disappears-if-error-occurred' of https://github.com/ojalehto/concrete5 into merge_preserve_checkboxes_new_page_type_valdiation_error
Add is_array check

Add is_array check for `$_POST['akID']` to prevent any possible edge
case where that returned an int etc
Merge pull request #1310 from mkly/merge_preserve_checkboxes_new_page_type_valdiation_error

Merge preserve checkboxes new page type valdiation error
Merge pull request #1309 from mkly/format_contains_string_commit

Format contains string commit
Merge pull request #1307 from mkly/double_dollar_signs

Remove Variable Variables
Merge pull request #1304 from mkly/fix_mysql_error_on_page_type_duplicate_add

Fix mysql Exception Shown on Page Type Add
Merge pull request #1308 from mkly/fix_permissions_key_add_typo

Fix type PermissionKey::add()
Merge pull request #1301 from mlocati/patch-4

Normalize description of view_page_in_sitemap key