Merge pull request #9 from Timple/master

Use abs values of speeds when determining whether to curtail speed

Correct parameter documentation

Only publish succes on succes, not on shutdown or preempt

Add minimum linear and angular speed configuration

Add acceleration parameters and fix Python naming

Fix #5: Add actionlib interface to diff_drive_go_to_goal

Add message when goal is achieved

Fix #4: Add handler for initialpose message

Fix typo in README

Add instructions on how to run the demo

Fix #3: Rename demo launch file after prior fixes

Normalize angles and fix conversion of quaternions to angles

Fix goal detection and stop controlling when at goal

Fix default value of kb