Rename method names that use TagElement in Candidate ElementExtractor.java

The TagElement is no longer used.  We changed the old method names with
new names
Rename method and variables in CrawlElement.java

TagElement.java was removed so we have to rename the old methods and
variables with new naems
minor error fix
change back to getTagName
fixed an error
Merge pull request #4 from ht92/issue-151

Rename methods and variables to fit the current crawlElement name