VAT ID validation fixes

Fix VAT ID being validated when it shouldn't be.
https://github.com/opencart/opencart/issues/943

Also fixes a problem where a ID of zero would pass validation.
Fix vat_validation function

Return 'invalid' on all errors to stop invalid characters, such as an
underscore, causing validation to pass. Fix problem where numbers with
spaces in return 'invalid'. Add missing ISO codes for Monaco and the
Isle of Man.
Fix Company ID and Tax ID in customer address

Fix Company ID and Tax ID display when adding a new customer address in
admin
Log append only
Merge pull request #51 from agung-wete/log_append

Log append only
Removed whitespace at end of PHP files

May reduce some "header already sent" errors
Closes #45 Company ID and Tax ID in order editor
Corrections to comments in .htaccess.txt
Fix for admin password reset protection
Closes #46 path disclosure
Fix error on deleting of return status

https://github.com/opencart/opencart/pull/975
Removed duplicate entry_customer_group

https://github.com/opencart/opencart/pull/975
Fixed cache delete when adding new language

https://github.com/opencart/opencart/commit/0223f66cdeb0a9b0468516ff291902a27f649b8b
Closes #48 additional DB table indexes
Whitespace standardization

See https://github.com/blog/967-github-secrets for viewing commits
without whitespace differences
Removed 'type' from image cache filename

Cached resized images should now match admin in all instances
https://github.com/opencart-ce/opencart-ce/blob/2bca5efa2090e5bc2a7159821819fe2082859f72/upload/admin/model/tool/image.php#L13
Revert "Removed 'type' from image cache filename"

This reverts commit 74dcebc6d83e70f167e54267a4eb830e9edba5d8.
Minor alignment correction
Spelling corrections
Additional DB table indexes