Increase mochiweb socket buffers up to 256KiB

This dramatically improves replication speed for large documents and
attachments and resolves replication test timeout for FreeBSD 10 and
OSX 10.9.2

Fixes COUCHDB-1986
Add documentation for new uuids.max_count option
Add What's New item about uuids.max_count option
Describe HTTP 403 response reasons for /_uuids resource
Update template helpers with utils methods for encoding and removing special characters
remove filter by in active tasks
Fix Active Tasks sidebar
dom cleanup
sidebar ui
Make Sidebar show all design doc functions
add metadata as a sidebar option