use enum instead of hardcoded string

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9694 5f5364db-9458-4db8-a492-e30667be6df6
isDisplayed() now works correct for HtmlImage, HtmlMap and HtmlArea

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9695 5f5364db-9458-4db8-a492-e30667be6df6
fix out test case; it works already for ff and IE11

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9696 5f5364db-9458-4db8-a492-e30667be6df6
add chrome

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9697 5f5364db-9458-4db8-a492-e30667be6df6
test fixes and rechecked with IE8

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9698 5f5364db-9458-4db8-a492-e30667be6df6
and again a test fix

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9699 5f5364db-9458-4db8-a492-e30667be6df6
some tags are special

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9700 5f5364db-9458-4db8-a492-e30667be6df6
simplified test case, restore the generic TestCaseTest

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@9701 5f5364db-9458-4db8-a492-e30667be6df6