Forked version with most UI and code improvements

[regorxxx]

Since this repository is no longer updated (and pull request have been there for years), I have forked the repository and added most of the request / improvements:

• Translate tool.
• Dictionary tool: English, Spanish, French, Chinese, Hindi, Arabic, Malay, Russian, Bengali & Portugese. Follows browser config.
• Google Image search tool.
• Print tool.
• GitHub tool.
• E-mail tool.
• Opacity option.
• Pressing 'Tab' key switches focus to buttons bar when it's opened -instead of following current position-, on first button.
• Pressing 'Esc' key closes buttons bar.
• 'CustomActions' option for custom buttons. Takes an array of objects with the same properties than the default ones (title, onClick, icon). Example is provided on html file.
• Scale configuration option to change overall size.
• Tooltip text on icons.
• General code cleanup.
• Popover is now animated.
• Buttons bar is now displayed at bottom if it can not be drawn at top.
• Icons are now buttons for all accessibility purposes (can be used with 'Tab' key).

I plan to maintain it and keep updating it.