Merge branch 'attachment-handling' of https://github.com/thororm/PrivateBin into thororm-attachment-handling

apart from resolving conflicts:
- added missing docs
- inlined functions that were used in only one location
- updated unit test to support all previews
- fixed a regression that displayed the preview even when there was no preview and too early

css/bootstrap/privatebin.css

@@ -68,12 +68,25 @@ body.loading {
 	margin-right: 8px;
 }
 
-#image img {
+#attachmentPreview img {
 	max-width: 100%;
 	height: auto;
 	margin-bottom: 20px;
 }
 
+#attachmentPreview .pdfPreview {
+	width: 100%;
+	height: 100vh;
+	margin-bottom: 20px;
+}
+
+.dragAndDropFile{
+        color:#777;
+        font-size:1em;
+        display:inline;
+}
+
+
 #deletelink {
 	float: right;
 	margin-left: 5px;