add in placeholders in ie7 & ie8
Merge pull request #910 from loomio/ie_placeholders

add in placeholders in ie7 & ie8
redirect user to home
Merge pull request #902 from loomio/bug/replace-leave-group-message

redirect user to home when leaving group
ensure show discussion works. inbox checks this requirement.
disable sign-up button when clicked
Merge pull request #920 from loomio/bug/inbox-mark-as-read-broken

fixes inbox mark as read.
Merge pull request #921 from loomio/fix/disable-signup-button-signup-form

disable sign-up button when clicked
New contribute icon & tooltip; title case for search placeholder
Merge pull request #922 from loomio/heart-icon

New contribute icon & tooltip; title case for search placeholder
inject TOS content