Feature/tool details

Hey John,

A while ago we Franklin Bristow and I added some code for impelmenting `ToolsClient.showTool()` and `ToolsClient.getTools()` similar to the functionality of BioBlend http://bioblend.readthedocs.org/en/latest/api_docs/galaxy/all.html#module-bioblend.galaxy.tools.  I think there was still some issues that needed to be addressed (it was mainly written for our specific purpose) but if it's useful feel free to merge it in and/or make suggestions.  Looks like it could be useful for issue #24.

Aaron