YAMLParser now supports YAML lists not parsed by the parser itself.

This means that list of type
```yaml
list:
  - test: "Hello"
  - test: "Hi"
```
will be parsed as a list of (ConfigurationSection)[src/main/java/it/fulminazzo/yamlparser/configuration/ConfigurationSection].
Totally reworked classes separation to respect packaging conventions.
Reworked FileConfiguration#addParsers method.
Renamed `it.fulminazzo.yamlparser.configurations` package to `it.fulminazzo.yamlparser.configuration`.
Made FileConfiguration and ConfigurationSection final.
Added support for escaped dot characters: now it will be able to use `\.` in paths to allow for dotted strings to be parsed.
Added support for BigDecimal notation when getting Number types.
Added `unquote` method to remove quoted strings when saving or loading.
Added `getOptional` method.
Now IConfiguration extends Serializable.
Reworked `FileConfiguration#newYaml` method to support older versions of SnakeYAML.
Fixed dotted test error.
Fixed `IConfiguration#getKeys` not returning an ordered set.
Fixed NullPointerException in `IConfiguration#throwException` method.
Updated README.md.
Updated FulmiCollection.

src/main/java/it/fulminazzo/yamlparser/configuration/IConfiguration.java

@@ -1013,7 +1013,8 @@ default String getCurrentPath() {
      * @param e      the e
      */
     default void throwException(String path, Object object, Throwable e) {
-        if (e instanceof RuntimeException || e instanceof InvocationTargetException) e = e.getCause();
+        if (e.getCause() != null && (e instanceof RuntimeException || e instanceof InvocationTargetException))
+            e = e.getCause();
         path = path == null ? "null" : path;
         String currentPath = getCurrentPath();
         if (currentPath != null && !currentPath.isEmpty()) path = currentPath + "." + path;