added nodes for creating and publishing point cloud messages
added launch and config files to demostrate how to use the nodes
remaps point cloud topic
initializes ros Node Handles after parsing the program input arguments
Create README.md
Update README.md

Included units for the publishing rate option.
added support for cylinder shape
added the shape type field for each point cloud description entry
added axis for showing world origin
corrected misspelled word
Merge pull request #2 from jrgnicho/issue_#1_add_new_nodes

Issue #1 add new nodes