Hotfix: Support for React 16 in <Gallery/> component

The issue, described in #150 was fixed in #202.

React v16 support

First requested in #166 and implemented in #171. Thanks goes to @Dog and @rek.

Hotfix: <DeleteButton> - Expected onClick listener to be a function, instead got a value of boolean type.

Fixed in #160.

Hotfix: <FileInput> cursor & <PauseResumeButton> invalid props fixes

• <FileInput /> issue described in #164.
• <PauseResumeButton /> issue described in #153.

Hotfix: PauseResumeButton doesn't work properly w/ concurrent chunking & auto-resume

Described in #151.

Hotfix: Missing canceled and deleted status in <Status />

referenced in #148

Switch to react-transition-group

Moved away from the deprecated/dead react-addons-css-transition-group. More info in #135.

Hotfix: Thumbnails missing when files are dropped into Gallery

Fixed in #142. Reported in #130.

Hotfix: Buttons will submit wrapping forms

Components in React Fine Uploader that contained <button> elements would submit wrapping forms when invoked. This was due to lack of a type='button' attribute on the these <button> elements, which made them submit buttons by default. This affected the following components:

• <CancelButton />
• <DeleteButton />
• <PauseResumeButton />
• <RetryButton />

Fix PropTypes warnings in React 5.5+

The only change was a move to the prop-types library for use of PropTypes validation, which is needed for React v5.5+.