improved ob_end_clean for download handler
fix register nonce and register catch errors
Correct get_country_locale for Japanese

Change and correct for the plug-in introduction to Japanese environment.
introduces the woocommerce_my_account_my_orders_query filter that helps customize the query in My Orders page. fixes #4450
fixed the indentation in templates/myaccount/my-orders.php
fixed conding standards in templates/myaccount/my-orders.php
Improved notices in the add_to_cart() method

- Moved the button markup out of the translation strings.
- Used get_cart_url() instead of get_permalink( wc_get_page_id( 'cart' ) ).
- Added some newlines to improve code readability.
Update abstract-wc-email.php

Adds a plain text replacement for the dollar sign encoded as html entity.
Add delete tax rates option to system tools
Rename new woocommerce_order_item_quantity filter

Renaming to avoid clash with pre-existing filter of the same name:
https://github.com/woothemes/woocommerce/blob/cdb1ad5e9ebcc440a459690ebf6862c374b01dbf/includes/class-wc-order.php#L1470
woocommerce_stock_amount rather than intval

Using woocommerce_stock_amount filter rather than intval cast
Don't resort meta in admin
wc_has_notice function
Merge pull request #4458 from ChromeOrange/master

Add delete tax rates option to system tools
Merge pull request #4457 from PURPORC/patch-1

Update abstract-wc-email.php
Merge pull request #4453 from GeertDD/add_to_cart_notices

Improved notices in the add_to_cart() method
Merge pull request #4461 from justinstern/master

Rename new woocommerce_order_item_quantity filter
Merge pull request #4451 from claudiosmweb/fix_4450

Introduces the woocommerce_my_account_my_orders_query filter
Merge pull request #4445 from toddlahman/master

improved ob_end_clean for download handler
Minor bugfix, missing comma

Missing comma causing errors in some cases