avoid URISyntaxException thrown on broken links

if page links to a broken URI like
"https://hostname.tld/#something=blah|somethingelse=blah1" whole
crawljax crashes on "java.net.URISyntaxException: Illegal character in
fragment at index 36:
https://hostname.tld/#something=blah|somethingelse=blah1".

It's kind of obvious from RFC 3968
(http://tools.ietf.org/html/rfc3986#page-24) - Fragment should not
contain a pipe "|" character (and also others).

This, however, should not break the crawling itself.
added a test case for the ULR fragment check, fixed a bug in the getBaseUrl method which would through an exception on a domain without any paths
Merge pull request #448 from crawljax/pr/447

Pr/447 #447 accepted and merged.