Fix tagcloud rendering behvaiour on special and wikipages

Additional content parsing is influenced by special page/template status.

An eyeball check on the following options (format=tagcloud):

1 link=all
2 link=none
3 template=TagCloud / link=none
4 template=TagCloud / link=all
5 widget=wordcloud / link=none
6 widget=wordcloud / link=all
7 widget=wordcloud / template=TagCloud
8 widget=sphere / link=none
9 widget=sphere / link=all
10 widget=sphere / template=TagCloud
remove the E_Strict warning with php > 5.1

As of php 5.1 the use of mktime() yields a warning (see http://php.net/manual/en/function.mktime.php). This simple change should fix this and is the recommended fix by the php devs.
Removing those warnings really helps to keep the server logs nice and clean ;)
Merge pull request #13 from jamasi/patch-1

remove the E_Strict warning with php > 5.1
bugfix (value filter does not filter out all empty values)

Added a case for empty values
Merge branch 'bugfix'
Merge pull request #16 from s7eph4n/master

bugfix (value filter does not filter out all empty values)
Update README.md
Create CONTRIBUTING.md
Update README.md
Update README.md
Update README.md
Update README.md
Update README.md
Update README.md