pending PR from humanmade/WordPress-Importer

[drzraf]

• [ ] 10 Add wp_import_existing_post filter from Trac #33721, 2015-11-18T05:27:01Z
• [ ] 76 Draft implementation of terms import for term-parent slug and term meta, 2016-07-23T21:25:48Z
• [ ] 82 Preselect existing usernames from dropdown during mapping, 2016-08-31T10:21:06Z
• [ ] 88 Make the importer resumable, 2016-10-07T22:32:33Z
• [ ] 94 Fix UI to successfully override admin header output, 2016-12-10T22:42:14Z
• [ ] 101 Re-use the local file, if available, 2017-03-01T11:29:55Z
• [ ] 104 Featured images, 2017-03-08T12:43:20Z
• [ ] 105 Better tag import, 2017-03-08T12:52:59Z
• [ ] 106 Add support for term meta data, 2017-03-08T22:39:17Z
• [ ] 108 Fix behaviour on falsey value returned by wxr_importer.pre_process.*, 2017-03-12T14:30:24Z
• [ ] 109 Check file is writable and it exists before unlink, 2017-03-14T13:59:57Z
• [ ] 119 Simple namespace-aware parsing, 2017-06-14T16:32:14Z
• [ ] 124 Fix bug whereby non-xml files in the media library are shown when "Select it from the Media Library" is clicked, 2017-06-15T16:50:10Z
• [ ] 126 Fix bug on mime-type of uploaded files, 2017-06-15T17:14:51Z
• [ ] 128 Match existing terms when possible., 2017-06-22T15:02:34Z
• [ ] 129 Improved hierarchical term handling, 2017-06-22T20:15:44Z
• [ ] 138 don't output remapping information, 2017-08-02T15:58:47Z
• [ ] 140 EventSource polyfill for IE10, IE11 and Edge, so ServerSent logger works, 2017-08-08T22:50:02Z
• [ ] 142 allow log messages to be sorted/paginated, 2017-08-09T19:27:26Z
• [ ] 144 style according to user's chosen admin-color scheme, 2017-08-09T21:53:28Z
• [ ] 145 extend the options that wp-cli can pass to the import, 2017-08-21T05:21:35Z
• [ ] 147 xml reader: don't block attempt to read from stdin using wxr-importer import php://stdin, 2017-08-21T05:49:33Z
• [ ] 152 Hook attach, 2018-04-03T14:32:14Z
• [ ] 153 correctly manage WXR post_id = 0, 2018-04-09T17:38:32Z
• [ ] 155 Map original ID based on username (optional, default to true), 2018-04-09T23:12:50Z
• [ ] 157 don't override existing post, 2018-04-20T16:06:41Z
• [ ] 158 Attachement is store to basename($url). urldecode() it, 2018-04-25T14:54:40Z
• [ ] 159 actually catch wp_insert_attachment errors, 2018-04-26T22:18:46Z
• [ ] 161 Post meta does not imported due to slashes. Added wp_slash to the post and post meta., 2018-07-04T13:56:44Z
• [ ] 165 Update CONTRIBUTING.md, 2018-08-21T12:24:39Z