Extracted follow link mechanism from NewContentCrawler to form FollowLinkCrawler to faciliate the implementation of OaiCrawler. NewContentCrawler is extends from  FollowLinkCrawler now.
Extracted follow link mechanism from NewContentCrawler to form FollowLinkCrawler to faciliate the implementation of OaiCrawler. NewContentCrawler is extends from  FollowLinkCrawler now.


git-svn-id: 293778eaa97c8c94097d610b1bd5133a8f478f36@3448 4f837ed2-42f5-46e7-a7a5-fa17313484d4

lockss/lockss-daemon,edina/lockss-daemon,lockss/lockss-daemon,lockss/lockss-daemon,lockss/lockss-daemon,lockss/lockss-daemon,lockss/lockss-daemon,edina/lockss-daemon,edina/lockss-daemon,edina/lockss-daemon,lockss/lockss-daemon,edina/lockss-daemon,edina/lockss-daemon,edina/lockss-daemon