option to read from config. Fix php 7 issues

[rodruiz]

Fixes:

• [BUG] Uncaught Error: Class 'Firebase\JWT' not found in ET_Client.php on line 207 #144
• Unable to validate App Keys(ClientID/ClientSecret) w/ Php 7.4.x [BUG] #159

To read the config file from a custom path:

$myclient = new ET_Client(true, false, null, true, '/path/to/config.php');

To ignore config file:

$params = array(...);
$myclient = new ET_Client(true, false, $params, false);

I can submit another PR to optimize and remove duplicate code from ET_Client constructor. Merging $params with $config should do the trick.

[PWalkow]

Why this fix wasn't merged yet?

[dsepulveda-pr]

is there another plan for this, why is still not merged?

[rodruiz]

@PWalkow and @dsepulveda-pr you can use my branch doing the following:

1- Add the following to your composer.json file

    "repositories": [
        {
            "type": "git",
            "url": "https://github.com/rodruiz/FuelSDK-PHP.git"
        }
    ]

2- Replace:

{
    "require": {
        "salesforce-mc/fuel-sdk-php": "1.4.0"
    }
}

with:

{
    "require": {
        "salesforce-mc/fuel-sdk-php": "dev-master"
    }
}

[JeremyDunn]

@manivinesh Looks like you have approved previous PRs. Would you mind reviewing this one? This sdk is unusable in PHP 7.4 at the moment.

[boxyashish]

can someone please review and merge this PR