fixed column widths
Merge pull request #93 from Useful-Innovation/johans-fixes

fixed column widths
added validation to edit time/purchase
Merge pull request #94 from Useful-Innovation/johans-fixes

added validation to edit time/purchase
added estimate preview function
Merge pull request #95 from Useful-Innovation/johans-fixes

added estimate preview function
added edit offered price
Merge pull request #96 from Useful-Innovation/johans-fixes

added edit offered price