CCBC-245 Generate debug for release build

It also reverts /OPT defaults so that it won't degrade performance and
size

Reference: http://msdn.microsoft.com/en-us/library/xe4t6fc1(v=vs.80).aspx
Reference: http://msdn.microsoft.com/en-us/library/958x11bc.aspx
Change-Id: I38930bfd8343be5a80f74eb639054d4e073a92a0
Reviewed-on: http://review.couchbase.org/28386
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>