WIP generating export links for the query export modal.

hard wired just for xls just now.
Including export formats in query meta data.
Put pdf and csv into default export formats.
Add new icons for export options

- added new icons for export options
Changed export modal to use new icons in a rudimentary way.
Add export-modal styles in styleguide

- added styles to export modal in styleguide
- changed some icon-classes
Fixed wrong class in export-options list

- fixed wrong class in export-options list
Merge branch 'dev' into feature/new-export-modal-icons

Signed-off-by: Alex Coles <alex@alexbcoles.com>

Conflicts:
	app/assets/fonts/openproject_icon/openproject-icon-font.eot
	app/assets/fonts/openproject_icon/openproject-icon-font.svg
	app/assets/fonts/openproject_icon/openproject-icon-font.ttf
	app/assets/fonts/openproject_icon/openproject-icon-font.woff
	app/assets/stylesheets/fonts/_openproject_icon_font.md
	app/assets/stylesheets/fonts/_openproject_icon_font.sass
Merge pull request #1446 from opf/feature/new-export-modal-icons

New export modal icons