* OK	Update to latest Bootstrap
* OK	Unify resource files between Flex and Admin (js, css etc.)
* Merge Flex _core.scss with Admin shared/_utils.scss
* Remove globalize.js entirely and all moment.js locale files
* OK	Apply .wide to parent tr of td.adminData with html editor or any other "wide" control (hide the label also)
* Find replacement for bootstrap-typeahead.js
* OK	bootstrapper-datetimepicker skinning is missing
* OK	Update bootstrap-editable.js
* OK	Update popper.js
* OK	Select2: multiple or taggable selects are not required to be hidden fields anymore > refactor.
* OK	Enclose all button labels in <span>, when an icon is available 
* OK	Readonly controls in .adminData: input[type=text][readonly].form-control-plaintext (formerly static labels)
* OK	Pass "postfix" additional viewdata to relevant numerictextbox instances
* OK	Refactor control toggling: 'data-toggler-for' instead of redundant toggle[...]() calls in every view
* Dropdown Groups: mehr als 2 Ebenen gehen nicht, daher bspw. EditorTemplates/ModelTree.cshtml umgestalten
* OK	window.openPopup > check whether 'fluid = true' should be passed
* OK	Locale Editors: Move hidden fields from td to another place to avoid space
* OK	Fix color picker control
* IStoreSelector, IAclSelector > refactor models & views and remove obsolete locale resources.
* OK	Validation styling for form controls
* OK	Shared\EditorTemplates\ButtonType.cshtml > Type names
* select2: .input-lg & .input-sm styling
* OK	All tables (.table) must be wrapped in div.table-responsive
* Apply .omega to all (last) table cells which contain action buttons to enable visibility toggling on hover. Apply .active-row to parent div to disable toggling, but keep other styling.
* OK	Add .alert-dismissable with &times; closer to all .alert elements
* OK	.form-check > .form-check-input + .form-check-label
* OK	Replace Html.SettingOverrideCheckbox () with new Html.SettingEditorFor()


TODOs Telerik grid:
====================
* OK	In ClientEvents.OnEdit: select2 change triggering only in editmode.
* OK	Grid inline editing: when a grid is editable, assign width (either px or %) to all columns except the last buttons col (otherwise: disco!)
* OK	.t-grid .t-last with command buttons: add *.HtmlAttributes(new { align = "right" }) to column (see ProductEdit > Promotion tab)
* OK	Move custom grid action buttons below or above a grid to the grid toolbar (see ProductEdit > Promotion tab > CrossSellingGridCommands(...) etc.)
* OK	.omega for last tds in Non-AJAX grids


TODOs BS4 Migration:
====================
* OK	Split Dropdown Buttons: .btn-dropwdown-split
* OK	Input Groups: .input-group-append/prepend & .input-group-text


TODOs Assets:
================
* select2 localization files


TODOs Frontend:
================
* .modal.modal-flex  >>  .modal-dialog.modal-flex