Currently, any connection failure (DNS resolution, timeout, connection refused) throws a fatal ConnectionErrorException. This interrupts the flow for applications that want to handle site downtime gracefully.

Changes made:
- Added `$suppress_connection_errors` property to Request class.
- Added `withoutStrictConnection()` chainable method.
- Modified `buildResponse` to check this flag. If set, it returns a generated Response object with HTTP 523 (Origin Unreachable) instead of throwing an exception.

Ref: Issue nategood#260 (Connection Errors Throw Exceptions)

The XML parser previously allowed loading of external entities by default on older PHP versions, creating a security vulnerability (XXE) where attackers could read local system files.

Changes made:
- Updated `parse` method in `src/Httpful/Handlers/XmlHandler.php`.
- Conditionally disabled `libxml_disable_entity_loader` for PHP < 8.0 to prevent XXE.
- Skipped this check for PHP 8.0+ to avoid deprecation warnings (as it is safe by default).

This commit addresses two distinct issues related to modern environment compatibility:

1. PHP 8.2 Compatibility:
   - Added `#[AllowDynamicProperties]` to the `Response` class.
   - This prevents "Deprecated: Creation of dynamic property" warnings in PHP 8.2+.

2. HTTP 100 Continue Bug:
   - Updated `Request::buildResponse` to detect and strip "HTTP/1.1 100 Continue" headers.
   - This ensures the parser correctly identifies the actual response headers and body, preventing malformed response objects.

1. Added support for 'application/vnd.api+json' (JSON:API) and 'application/problem+json' (RFC 7807). This allows users to use short names 'json_api' and 'problem_json'.
2. Added null checks in `getFullMime` and `supportsMimeType`. This prevents "Deprecated: Passing null to parameter" warnings in PHP 8.1+.

1. Modified `Bootstrap::init` and `Bootstrap::pharInit` to check `self::$registered` before registering autoloaders. This prevents duplicate autoloader registration when the library is included multiple times or in complex environments.
2. Updated `registerHandlers` to map `application/vnd.api+json` and `application/problem+json` to the existing `JsonHandler`. This ensures these common API formats are parsed automatically.

1. Updated `fromString` to handle duplicate headers (e.g., multiple Set-Cookie lines). Previously, subsequent headers with the same name would overwrite the first one. They are now concatenated with a comma as per RFC 2616.
2. Added `#[ReturnTypeWillChange]` attributes to `ArrayAccess` and `Countable` methods to suppress deprecation notices in PHP 8.1+.

Added `stripBom()` call to `FormHandler::parse`. 
Without this, responses starting with a Byte Order Mark would result in the first key of the parsed array being corrupted/inaccessible.

1. Added validation to `Httpful::register` to ensure the mimeType is a valid string.
2. Updated `Httpful::get` to handle null/empty mime types explicitly.
3. Bumped VERSION constant to 0.3.0 to signify the inclusion of PHP 8.1/8.2 compatibility fixes, security patches (XXE), and modern JSON support.

1. Created `src/Httpful/Exception.php` as a base exception class.
2. Updated `ConnectionErrorException` to extend `Httpful\Exception`.
This allows developers to catch all library-specific exceptions using `catch (\Httpful\Exception $e)`.

1. Bumped version to 0.3.0 to match the code updates.
2. Updated PHP requirement to >=7.2 to ensure stability with modern features.
3. Explicitly added `ext-json` and `ext-simplexml` requirements since the library relies on them.
4. Locked `phpunit/phpunit` to ^8.0 || ^9.0 to prevent build failures caused by incompatible newer versions of PHPUnit being installed by default.