Added support for YAML-CPP 0.5+.

The new yaml-cpp API removes the "node >> outputvar;" operator, and
it has a new way of loading documents. There's no version hint in the
library's headers, so I'm getting the version number from pkg-config.
fixed header installation directory
Merge pull request #144 from piyushk/patch-1

fixed header installation directory navfn
Merge pull request #140 from ktossell/hydro-devel

Added support for YAML-CPP 0.5+.
New Overwrite Methods
updateMap method
Fix for #68
Fix for inflation memory problems
InfIsValid #128
Static layer can recieve updates and accept non-lethal values
Map Server can serve maps with non-lethal values
Obstacle layer uses track_unknown_space parameter
Footprint layer is not longer created as top-level layer (used as part of obstacle layer instead)
Improved Global Planner (from Groovy branch)
Misc. other commits from Groovy Branch
Better handling of frame param in MapGridVisualizer
Cheat factor for end of DWA Plans
Merge pull request #146 from DLu/hydro

Updates from Groovy Branch
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