Adds ability to specify a template for exceptions retrieved from Exception::getPrevious
View: correctly validate input in PartialLoop

Change the condition to be more safe and intuitive.

Closes #4545
PartialLoop: rewrite input check even better
PartialLoop: simplify check, remove comment
Zend\Form - trying to get() a non-existent element should raise an exception
Zend\Form - Exception when try to get() element that doesn't exist should use sprintf, message should not use punctuation & should not import the exception class
Fix Request.php so HTTP_HOST will take precedence over SERVER_NAME

In nginx for example the SERVER_NAME is the first value which is configured after server_name

for example:
server_name server1.com server2.com serverN.com

SERVER_NAME in php env will be server1.com
While HTTP_HOST will be the requested URL
Update Request.php
Update Request.php
Update Request.php
Update RequestTest.php
PartialLoop: unit test for null values
aad test to console exception strategy
Update RequestTest.php

Added test for spoofed HTTP_HOST
Update Request.php
Merge pull request #4542 from basz/master

Adds ability to specify a template for exceptions retrieved from Exception::getPrevious
Merge branch 'hotfix/4542'

Close #4542
Merge pull request #4546 from yogipw/hotfix/4545

View: correctly validate input in PartialLoop
[#4546] Updated test

- to use setExpectedException()
Merge branch 'hotfix/4546'

Close #4546
Fixes #4545