Many fixes found in issues, plus some

[Phlow2001]

• options combine per-FileReader
• Prevent calling FileAPIProxy.init() multiple times
• Add option overrides for container css position, css offset and dom append point, to allow for use in bootstrap modal.
• Add option for trigger to allow for input styling plugins (bootstrap-filestyle)
• Add interval-based PercentLoaded checks to ensure ready when actually ready