* Use constants for max contact fields and max group membership columns * Tweaks to twitter activity claiming that deals with webhooks already being claimed, shows errors etc * Rename form field to be consistent with the constants we use * Writes only now use XLSLite, more coverage * Limit number of groups for group memberships in results exports * Swicth message export to use XLSLite * Fix default ACL value for S3 files * Add WeChat (for beta users)