Restore missing buttons in caption bar

Those button, being width: 100% and display: block were not displayed
AND were pushing out also the slideshow buttons.

umap/static/umap/base.css

@@ -202,6 +202,8 @@ button.flat,
     padding: 0;
     text-align: left;
     min-height: inherit;
+    width: initial;
+    display: initial;
     text-decoration: underline;
 }
 .help-text, .helptext {

umap/static/umap/js/umap.js

@@ -1744,16 +1744,16 @@ L.U.Map.include({
     this.permissions.addOwnerLink('span', container)
     if (this.options.captionMenus) {
       L.DomUtil.createButton(
-        'umap-about-link',
+        'umap-about-link flat',
         container,
-        ` — ${L._('About')}`,
+        L._('About'),
         this.displayCaption,
         this
       )
       L.DomUtil.createButton(
-        'umap-open-browser-link',
+        'umap-open-browser-link flat',
         container,
-        ` | ${L._('Browse data')}`,
+        L._('Browse data'),
         this.openBrowser,
         this
       )

umap/static/umap/map.css

@@ -600,6 +600,13 @@ ul.photon-autocomplete {
 .umap-main-edit-toolbox h3 {
     display: inline;
 }
+.umap-caption-bar button {
+    margin-left: 10px;
+}
+.umap-caption-bar button + button:before {
+    content: '|';
+    padding-right: 10px;
+}
 .umap-main-edit-toolbox .umap-user {
     color: #fff;
 }