[FIX] don't coerce values to str before writing them to the worksheet in excel export
[FIX] don't coerce values to str before writing them to the worksheet in excel export

especially since xlwt is perfectly able to deal with unicode instances without blowing up like a 'tard
splbio/openerp-web,splbio/openerp-web,gisce/openerp-web,gisce/openerp-web,vnc-biz/openerp-web,MarkusTeufelberger/openerp-web,vnc-biz/openerp-web,vnc-biz/openerp-web,vnc-biz/openerp-web,splbio/openerp-web,gisce/openerp-web,MarkusTeufelberger/openerp-web,MarkusTeufelberger/openerp-web