Complete rework on the code.  Fixed renderSlideshowParserFunction() calling a non-existant function.  Renamed explode_assoc to explodeArguments, cleaned up the logic, and put in error checking.  Added documentation to everything.  Changed the hook registration to use the standardized $wgHooks[ParserFirstCallInit] method.  Fixed renderSlideshowTag() calling the non-static renderSlideshow() function statically.  Cleaned up the hooks file formatting.
Moved the extension credits to parser hooks.  Fixed the static/non-static type jumble going on.  Fixed another non-existant function call in renderSlideshowParserFunction().
Extension tested with both tag and function calls.  Works as expected.  Bumping this to verison 1.0 since it is well rounded now.
Missed a static declaration
Merge pull request #1 from Alexia/master

Fixing all the things!