Add link to zip download

Adding the complementary part to mkly's changes, making it more friendly for newcomers to know how to get the latest development build without having to know how to navigate GitHub.
Added possibility to specify translation contexts
What about introducing the use of msgctxt for ambiguous translations? So translators can better understand how to translate a text.
For example: 'To %s' may have two different translations when used as "Send to recipient" or as "End of a date interval".
The modified web/concrete/elements/permission/duration.php shows a possible implementation.
Remove hardocded textarea width from form block output
The translation of `%ss` doesn't make sense
The function `on_before_render()` of the concrete5_Controller_Dashboard_Workflow_Me class contains the code `t('%ss', …)`, where the … may be `Page`, `File` or `User`.
Anyway, with that code, translators have to literally translate `%ss`, which doesn't make sense: only in English plural forms are composed by adding an 's' after a word (and even in English this is not always true).
My solution is to translate every case.
Another, more elegant solution, would be to change the /web/concrete/config/install/base/permissions.xml file, adding a new xml attribute (let's call it `tabName`) containing the text for the tabs for each one of the `category` nodes of the `workflowprogresscategories` node. This implies we have to modify the function `importWorkflowProgressCategories()` of the /web/concrete/core/libraries/content/importer.php file and the `Concrete5_Model_WorkflowProgressCategory` class to manage this property.
Normalization of concrete5 name
There are some locations where concrete5 is written as Concrete5 (o just Concrete). This commit fix these, using always the lowercase "concrete5"
added option for autonav templates to ignore exclude_nav attributes (useful for breadcrumb menu)
Added file description to data returned by the files/get_data tool
Avoid possible double page checkout

Let's hide the panel with the "Edit this Page" button
I've seen (even from myself) that users often click on the
Update web/concrete/blocks/image/composer/thumbnail.php

localization of the title for crop image panel
Fix access denied message in sitemap selector

The page concrete/tools/sitemap_search_selector.php, when users don't
have access, says "Access Denied. You do not have access to sitemap
permissions". I think that users don't have access to the sitemap, not
to its permissions. Is that right?

As a minor change, I also splitted the two phrases in two different
sentences to be translated, so translators don't have to translate
the "Access Denied." part.
avoid caching of securimage

http://www.concrete5.org/developers/bugs/5-6-0-2/securimage-only-reloads-the-first-time-it-is-clicked-on/
Bugfix: External link bug

If you install concrete5 to document root and put page list block under
2nd level then the external link doesn't work.
Fix custom style lost after adding layout

This pull request fixes the fact that custom styles are lost when
adding a layout to a page with blocks having custom styles.

Bug tracker: http://www.concrete5.org/index.php?cID=394701
set fixed height in slideshow block
determine max height of slideshow images
constant to hide concrete5 version number

as mentioned here http://www.concrete5.org/community/forums/chat/visible-version-number-in-source-code/
don't output unnecessary jquery UI in form block

Take 2 (see https://github.com/concrete5/concrete5/pull/672 for prior discussion).
Also outputs CSS to header (not footer) if needed.
Fix blocktype sort mismatches

Removes gaps in the btDisplayOrder sequence whenever a blocktype is deleted. This prevents future problems when sorting the remaining blocktypes in the dashboard list.
Add link to pages in Bulk SEO Updater

When managing seo fields in the Bulk SEO Updater, it's often useful to
take a look at the page.
Add link to pages in Bulk SEO Updater and fix css

When managing seo fields in the Bulk SEO Updater, it's often useful to
take a look at the page.