[add] release date info

Author: mkozhukh

assets/theme.css

@@ -576,3 +576,8 @@ html, .footer{
         padding-bottom: 8px;
     }
 }
+
+.release_date{
+    color: #a0a0a0;
+    margin-left:20px;
+}

data/desktop/whats_new.md

@@ -2,12 +2,12 @@ What's new
 ====================
 
 {{index
-- desktop/whats_new_2_5.md
-- desktop/whats_new_2_4.md
-- desktop/whats_new_2_3.md
-- desktop/whats_new_2_2.md
-- desktop/whats_new_2_1.md
-- desktop/whats_new_2.md
+- desktop/whats_new_2_5.md <span class="release_date"> July 24, 2015</span>
+- desktop/whats_new_2_4.md <span class="release_date"> May 22, 2015</span>
+- desktop/whats_new_2_3.md <span class="release_date"> March 24, 2015</span>
+- desktop/whats_new_2_2.md <span class="release_date"> January 23, 2015</span>
+- desktop/whats_new_2_1.md <span class="release_date"> November 26, 2014</span>
+- desktop/whats_new_2.md   <span class="release_date"> September 12, 2014</span>
 - desktop/whats_new_1_10.md
 - desktop/whats_new_1_9.md
 - desktop/whats_new_1_8.md

data/desktop/whats_new_2.md

@@ -1,7 +1,9 @@
 Version 2.0
 ==============
 
-### Major features
+<span class="release_date">released on September 12, 2014</span>
+
+## Major features
 - [Promises API for all ajax operations](helpers/ajax_operations.md)
 - [Progress bars and overlays](desktop/progress.md)
 - Improved keyboard navigation
@@ -21,7 +23,7 @@ Version 2.0
 
 If you are updating from Webix 1.x - please check the migration.md
 
-### Minor features
+## Minor features
 - [custom height for header lines in datatable](datatable/headers_footers.md#customheightforheaderandfooter)
 - dark style for carousel
 - [getState api](api/dataprocessor_getstate.md) for dataprocessor
@@ -37,7 +39,7 @@ If you are updating from Webix 1.x - please check the migration.md
 - [suggest](desktop/suggest.md) for text editors
 
 
-### Fixes
+## Fixes
 
 - ability to define popup as raw json config
 - active style for danger button

data/desktop/whats_new_2_1.md

@@ -1,6 +1,8 @@
 Version 2.1
 =================================
 
+<span class="release_date">released on November 26, 2014</span>
+
 ##Major features
 
 - Better compatibility with Bootstrap and [jQuery](desktop/jquery.md)

data/desktop/whats_new_2_2.md

@@ -1,6 +1,8 @@
 Version 2.2
 =================================
 
+<span class="release_date">released on January 23, 2015</span>
+
 ## Breaking changes
 
  - width and height settings for all data components include size of scrollbar (so component will always take exactly the same size as was defined by width and height properties)

data/desktop/whats_new_2_3.md

@@ -1,6 +1,8 @@
 Version 2.3
 ============
 
+<span class="release_date"> released on March 24, 2015</span>
+
 ## Breaking changes
 
 - Default [parse format](api/i18n_parseformat_other.md) is changed for datepicker and calendar controls from *"%Y-%m-%d"* to *"%Y-%m-%d %H:%i"*. Both of them can be altered within current locale. 

data/desktop/whats_new_2_4.md

@@ -1,6 +1,8 @@
 Version 2.4
 ============
 
+<span class="release_date">released on May 22, 2015</span>
+
 ## New features
 
 - [Portlet](desktop/portlet.md) widget

data/desktop/whats_new_2_5.md

@@ -1,8 +1,9 @@
 Version 2.5
 =====================
 
+<span class="release_date">released on July 24, 2015</span>
 
-##New Features
+##New features
 
 - Support of Microsoft Edge, default browser of the upcoming Windows 10
 - Ability to [disable time periods](desktop/calendar.md#disablingdatesandtimeslotsincalendar) for Calendar widget