Improve translation of "Edit block" message

This allows, for instance, to reverse the order of words.
Removed unused variables and outdated comments
Simplify call to getValue when called with 2 parameters

If func_num_args() is 2 then we can avoid call_user_func_array
and call $av->getValue() directly (that's faster)
make area name translatable
Fix outdated cache after saving tracking codes
class added to login form

it's a bit tricky to style the login form since we don't have a
class. This PR adds a class, no sure about the official name
conventions here but it makes styling much easier.
fix mixin call

the order of the parameters is wrong
https://github.com/concrete5/concrete5/blob/master/web/concrete/css/ccm_app/twitter_bootstrap/mixins.less#L139
class for "forgot password" form
Let's deprecate BLOCK_NOT_AVAILABLE_TEXT

This define contains a localized text to be shown when a block is no
longer available.
Let's deprecate it since:
1. after calling Localization::changeLocale() this define contains a text
in the wrong language.
2. there's no reason to have manage this text represented with a define
whereas all the other messages are represented directly
User selector update to make it clearable

Made the single user selector clearable to make it consistent with the multi user selector and the image selector.  Also fixed a problem with only one ccm_triggerSelectUser ever being accepted.  If you passed in a custom javascript function it would either never be used it or only be used for all user selector instances on the page.

To illustrate the problem:

$user_selector->selectUser('field1');
$user_selector->selectUser('field2',null,'doSomething');

the old generated javascript:

user selector 1: 
ccm_triggerSelectUser = function(uID, uName, uEmail) {
   …
}

user selector 2:
ccm_triggerSelectUser = function(uID, uName, uEmail) {
	doSomething(uID, uName);
}

ccm_triggerSelectUser has been overwritten at the window level, the first triggerSelectUser will never get called.
Updated attribute key insert id 

When using the mysqli adodb driver (which I use for transactional
 support), you can't have any queries between an insertion and a request for
 the insert id or adodb will return 0.
disable notices for missing en_US translations
Fix comments and user messages
Remove river_theme symlink

Remove river_theme symbolic link
Merge pull request #1422 from mkly/remove_river_theme_symlink

Remove river_theme symlink
Fix JS error when editing user by using double quotes in jQuery selector for state/province.

Double quotes are required in selector for values which contain spaces.
Merge pull request #1423 from Shotster/fix_state_prov_selector

Fix statue/province JS error when editing user by using double quotes.
Adding version numbers underneath heading in install pages

When installing concrete5 there is nothing to indicate what version you
are installing, these extra lines make this clear.
Adjustment to translation string to include constant
Merge pull request #1424 from Mesuva/Addition-of-version-number-to-install-screens

Adding version numbers underneath heading in install pages