Added Reports/SentTo and Segments to Campaign

Segment options were added to the Campaign class to allow
GetAllMembersForList to filter the list by segment.
Added Report/SentTo method to allow MailChimpManager and associated
classes.
Added support for saved segments.
Merge pull request #52 from rafaelbac/master

Added support for saved segments.
Update README

Updated status
Merge pull request #53 from scottuhler/master

Added Reports/SentTo method as well as Segments to Campaigns
Fix for #34
Fix for #11

Looks like I misread the API:
http://apidocs.mailchimp.com/api/2.0/campaigns/list.php It's not an
array of structs for the filterParam, just a struct.
Fixes for #10

The ints default to 0 when they are not nullable, which acts as a
filter.  This is bad.  Switched to nullable -- this should allow the
MailChimp API to interpret these optional fields as 'not present'.
Added wercker build support
Updated wercker build box
Updated wercker steps
Updated wercker config
Added Merge Vars
Fixed MemberActivityResult
Removed wercker support.  Added AppHarbor solution

AppHarbor solution does not have tests
Merge pull request #54 from DDtMM/master

Adding some mergeVars functions
Added 'making contributions' section to readme
Completed MergeVars implementation
Fix Issue #27
Updated README

Attempted to improve readability