Fix divider and leading zero positioning

Closes #188

Author: wojtekmaj

src/DateTimePicker.less

@@ -36,6 +36,11 @@
       white-space: pre;
     }
 
+    &__divider,
+    &__leadingZero {
+      display: inline-block;
+    }
+
     &__input {
       min-width: @digit-width;
       height: calc(100% - 2px);