style: fixed formating
refactor: removed validators, events can return false
Breaking change
test: fileAdded custom validation tests
test: event can return value
test: test if file was already uploaded
feat: ResumableFile helper methods getType and getExtension.
feat: constructors of ResumableFile and ResumableChunk exposed throught api
test: tests for ResumableFile helper functions
docs: changlog updated
fix: getExtension fixed