Adds MotD and Message model as well as tests

This commit adds the MotD model for storing and retrieving
messages-of-the-day.

It also adds a model for messages. Messages have an author as well as a
thread they belong to, the thread can be read by a specific number of
authors. FUrthermore, the message model supports system messages.

This commit introduces a number of needed changes:
- Character is now implementing the CharacterInterface
- MissingCharacter and SystemCharacter are supporting "pseudo-characters"
- trait MockCharacter implements non-implemented methods for
  MissingCharacter and SytemCharacter
- Characters are now soft-deletable. Models wanting to load soft-deleted
  characters need to fetch them eagerly.

Closes #17

Author: Vassyli

bootstrap/bootstrap.php

@@ -1,3 +1,5 @@
 <?php
 
-$autoloader = require __DIR__ . "/../vendor/autoload.php";
+$autoloader = require __DIR__ . "/../vendor/autoload.php";
+
+\date_default_timezone_set("UTC");

composer.json

@@ -7,7 +7,8 @@
   },
   "require": {
     "monolog/monolog": "1.16.0",
-    "doctrine/orm": "2.5.*"
+    "doctrine/orm": "2.5.*",
+    "gedmo/doctrine-extensions": "*"
   },
   "require-dev": {
     "phpunit/phpunit": "*",

composer.lock

@@ -6,6 +6,7 @@
 /**
  * Exception if a specific, required argument is missing
  */
-class ArgumentEmptyException extends CoreException {
+class ArgumentEmptyException extends ArgumentException
+{
 
 }

src/Exceptions/ArgumentEmptyException.php

@@ -0,0 +1,12 @@
+<?php
+declare(strict_types=1);
+
+namespace LotGD\Core\Exceptions;
+
+/**
+ * Exception if a specific, required argument is missing
+ */
+class ArgumentException extends CoreException
+{
+    
+}

src/Exceptions/ArgumentException.php

@@ -0,0 +1,12 @@
+<?php
+declare(strict_types=1);
+
+namespace LotGD\Core\Exceptions;
+
+/**
+ * Exception if a specific combination of model values is invalid.
+ */
+class InvalidModelException extends CoreException
+{
+    
+}

src/Exceptions/InvalidModelException.php

@@ -0,0 +1,11 @@
+<?php
+declare(strict_types=1);
+
+namespace LotGD\Core\Exceptions;
+
+/**
+ * Exception if a specific, required argument is missing
+ */
+class IsNullException extends CoreException {
+    
+}