Port to Guzzle 6

Guzzle 5 handles URLs incorrectly. This required upgrade to Graby 2.0,
which is still in development. This also bumps required PHP version to 5.6.

.travis.yml

@@ -5,13 +5,12 @@ language: php
 
 matrix:
     include:
+        - php: 7.3
         - php: 7.2
         - php: 7.1
         - php: 7.0
           env: CS_FIXER=true LINT_JS=true
         - php: 5.6
-        - php: 5.5
-        - php: 5.4
           env: DEPLOY=true
     fast_finish: true
 

composer.json

@@ -3,21 +3,22 @@
     "description": "Multipurpose rss reader, live stream, mashup, aggregation web application",
     "type": "project",
     "require": {
-        "php": ">= 5.4",
+        "php": ">= 5.6",
         "bcosca/fatfree-core": "^3.6",
         "danielstjules/stringy": "^3.1",
         "fossar/tcpdf-parser": "^6.2",
         "fossar/twitteroauth-php54": "^0.7.3-beta",
-        "fossar/guzzle-transcoder": "^0.0.3",
-        "guzzlehttp/guzzle": "^5.3",
-        "guzzlehttp/log-subscriber": "^1.0",
+        "fossar/guzzle-transcoder": "^0.1.0",
+        "guzzlehttp/guzzle": "^6.3",
+        "guzzlehttp/psr7": "^1.5",
         "fossar/htmlawed": "^1.2.4.1",
-        "j0k3r/graby": "^1.6",
+        "j0k3r/graby": "2.0.x-dev",
         "linkorb/jsmin-php": "^1.0",
         "lordelph/icofileloader": "^1.0",
         "mibe/feedwriter": "^1.0",
         "monolog/monolog": "^1.0",
         "natxet/CssMin": "^3.0",
+        "php-http/guzzle6-adapter": "^1.0",
         "simplepie/simplepie": "^1.3",
         "smottt/wideimage": "^1.1",
         "willwashburn/phpamo": "^1.0",
@@ -40,7 +41,7 @@
     },
     "config": {
         "platform": {
-            "php": "5.4.45"
+            "php": "5.6.0"
         }
     },
     "scripts": {