WIP: erp5_officejs: Integrate wickedgrid (Jquery Spreadsheet) gadget to officejs

This gadget integrates WickedGrid (A Javascript based spreadsheet editor) to officeJS https://github.com/Spreadsheets/WickedGrid/

This gadget currently support

• Editing Cells
• Adding New Cells
• Highlighting Cells
• Exporting to HTML
• Highlighting multiple rows and column (Not in the commit)
• Menu (Not in the commit)
• Adding more than one spreadsheet (Not in the commit)

Features in pipeline

• Deleting Cells (In progress)
• Undo and Redo (Next)
• Formulas (Works partially)
• Copy and Paste
• Deleting Spreadsheets
• Small UI issues here and there

All these above feature are partially implemented or are broken because the original maintainer didn't have time to fix them so I am spending some time to get a basic version up.

You can track my progress here - https://github.com/Spreadsheets/WickedGrid/pulls?utf8=%E2%9C%93&q=is%3Apr%20author%3Ahardikj%20