Remove 'Summary' heading from member#show
Add lead member summary sentence

Contains electorate and dates of membership.

2 TODOs
add TODO about date format
replace member summary table with sentence pattern.
Convert to HAML, of sorts
Make the helper return a date
Change '1 Jul 2014' to month year format: 'July 2014'
Remove extra new line
Merge pull request #386 from openaustralia/cleanup_member_show

Cleanup member show