[FIX] web: listview editable, non editable elements

When editing a line, leave the buttons visible.
Also remove the 3px gap between fields so that readonly field texts
does not move when entering the edition mode.

addons/web/static/src/css/base.css

@@ -2165,11 +2165,11 @@
   opacity: 0;
   display: block !important;
 }
-.openerp .oe_list.oe_list_editable.oe_editing .oe_edition .oe_list_field_cell {
+.openerp .oe_list.oe_list_editable.oe_editing .oe_edition .oe_list_field_cell:not(.oe-button) {
   color: transparent;
   text-shadow: none;
 }
-.openerp .oe_list.oe_list_editable.oe_editing .oe_edition .oe_list_field_cell * {
+.openerp .oe_list.oe_list_editable.oe_editing .oe_edition .oe_list_field_cell:not(.oe-button) * {
   visibility: hidden;
 }
 .openerp .oe_list.oe_list_editable.oe_editing .oe_m2o_drop_down_button {

addons/web/static/src/css/base.sass

@@ -1866,7 +1866,7 @@ $sheet-padding: 16px
             opacity: 0
             display: block !important
     .oe_list.oe_list_editable.oe_editing
-        .oe_edition .oe_list_field_cell
+        .oe_edition .oe_list_field_cell:not(.oe-button)
             *
                 visibility: hidden
             color: transparent

addons/web/static/src/js/views/list_view_editable.js

@@ -420,7 +420,7 @@ ListView.include(/** @lends instance.web.ListView# */{
      */
     resize_field: function (field, cell) {
         var $cell = $(cell);
-        field.set_dimensions($cell.outerHeight(), $cell.outerWidth()-3); // -3 to have a gap between fields
+        field.set_dimensions($cell.outerHeight(), $cell.outerWidth());
         field.$el.addClass('o_temp_visible').css({top: 0, left: 0}).position({
             my: 'left top',
             at: 'left top',