Merge pull request #1282 from ghost1227/master

Fix for #1250
Restore time() in class-wp-session.php. Apparently using current_time('timestamp') broke sessions
Fixed incorrect currency code. Closes #1288
Change capability for EDD Add Ons and System Info sub menus

The "install_plugins" capability gives only WP super admins on WP multisite installs access to Add Ons, System Info Upgrade screen.
This is how it should be.
On single WP installs the Admin still can access these sub menus.
see
http://codex.wordpress.org/Roles_and_Capabilities
Fix undefined variable. #1270 Props @abeel
Remove is_user_logged_in() from edd_has_user_purchased()
Added a post installation hook.
[i18n]>French and pot updates
Updated readme with campaign tracking links
Merge pull request #1296 from fxbenard/master

[i18n]> french and pot updates
Correct test mode check in edd_complete_purchase
Merge branch 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads
Merge branch 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads
Updated release tag for edd_after_install to 1.7
Use transient for post-activation hook.
Add data-download-id to cart rows and make sure ID rows are unique. CLoses #1284
Change Download to Free Download. CLoses #1253
Correct wrong version number in readme
Fix incorrect redirect when selecting a payment method with ajax disabled and permalinks set to default. Closes #1290
Hide discount field is cart total is 0.00. Closes #1286