[FIX] Move bootstrap.css outside from the single css file generate.

[FIX] Move bootstrap.css outside from the single css file generate.
Without that, OpenERP become unusable in IE due to the follows limitations:
   - All style tags after the first 31 style tags are not applied.
   - All style rules after the first 4,095 rules are not applied.
   - On pages that uses the @import rule to continously import external style sheets that import other style sheets, style sheets that are more than three levels deep are ignored.
  (http://support.microsoft.com/kb/262161/en)

bzr revid: jke@openerp.com-20140307174411-hejt3x324nlv6tjr