re #91 : Exceptions are not allowed in __toString() magic methods. Catch them and trigger a user error instead.
Code cleanup
Fix typo
re #91 : Refactor filesystem stream package

- Implement KFilesystemStreamFactory to allow creating stream objects from a URL and register and unregister new stream types. Factory is implement as a singleton and is warmed up when Koowa is instantiated.
- Implement KFilesystemStreamAdapter to expose KFilesystemStream objects to the native PHP stream functions.
- Implement KFilesystemStreamAbstract to work as a decorator for the native PHP stream functions.
- Implement KFilesystemStreamBuffer to expose a memory and temporary file stream buffer.
re #91 : Create template buffer using filesystem.stream.factory
re #91 : Sync with changed in FilesystemStream API

- Lazy create the response stream only when it's being requested.
- De not differentiate between path and string content
Merge remote-tracking branch 'origin/develop' into develop