Check ini_get is not disabled before using it

Basing off pull request 413, fixing tests

As described in #492, ini_get may often be disabled in production environments, causing warnings to be generated (and NULL) to be returned. This change checks that ini_get is usable (otherwise function_exists will return FALSE) before using it, preventing the warnings while introducing no functional change.

Keep Response statusCode as integer, not string

Performance updates for formatting values

Provides fluent interface

Adjusts the conditional logic when building the field XML to only call htmlspecialchars on unknown values.

Merge changelog to develop

Merge develop to master for new release

fix for PHP 5.3

Merging develop to master for new release

#474 - Using GET method when extracting remote file with stream.uri

Add Guzzle 6 Adapter implementation

Fix document syntax

Remove duplicated word

 Add Guzzle3 Client Adapter

usleep after curl_multi_select -1

Enable Simple Group Format

Correct language about RealtimeGet query use

According to these php bugs:

* https://bugs.php.net/bug.php?id=61141
* https://bugs.php.net/bug.php?id=63842

thats what we should do.

I came across this issue when trying to make the ParallelExecution
working on my CentOS 7.3 box. It spinlooped inside the changed loop.

Also guzzle is doing the same thing:

https://github.com/guzzle/guzzle/blob/master/src/Handler/CurlMultiHandler.php#L103

I am not sure if the timeout needs to be configurable and if the choosen
value (100) is good.

Update plugins.md

small fix for non-working external links ("wikilink")