Correct type of prefer_forward penalty member variable

The setter and the configuration treat this value as a double, this
makes sense when comparing it to the other costs. However, it was stored
as a bool. This seems like a typo.
Ignore pyc files from running in devel
Keep consistent allignment_cost scale

Use the configured alignment cost instead of resetting to 1.0. This
condition (farther from goal than forward_point_distance) is probably
met at the start of navigation, it seems this cost should be obeyed
until the robot gets close, then ignored completely.
Merge pull request #153 from contradict/simple-bug-fixes

Simple bug fixes
Merge pull request #154 from contradict/consistent-alignment-cost-scale

Keep consistent allignment_cost scale
Merge remote-tracking branch 'ros-planning/hydro-devel' into hydro-devel