Merge pull request #128 from johnheroy/master

Modals to guide through import .xlsx process
Changed Standard modals into Bootbox Modals
Cleaning up
Merge pull request #132 from fsbatista/angular

Changed Standard modals into Bootbox Modals
Issue Solved - Initial commit appears after first Import
Merge pull request #133 from fsbatista/angular

Issue Solved - Initial commit appears after first Import
Remove legacy js files in app/
Call renderSheet from shell.js only and attach current workbook instance to currentWorkbook factory, resolves #131