Add common VHDL file extensions
Add composer.lock to JSON filenames

[Composer](http://getcomposer.org] uses one configuration file (composer.json) and
one lock file (composer.lock). They both use valid JSON.

Example: https://github.com/OpenBuildings/jam/blob/master/composer.lock
Add five new extensions to XML, YAML in support of ROS usage.

These extensions are in common use in packages part of ROS, the Robot Operating System.

[urdf](http://wiki.ros.org/urdf), [srdf](http://wiki.ros.org/srdf): These are Robot Description Files, XML documents which describe the physical realities of a robotics platform, for the purposes of consumption by common libraries.

[xacro](http://wiki.ros.org/xacro) is for input files to the XML macro processor xacro, which is used in ROS to output URDF and SRDF files.

[launch](http://wiki.ros.org/roslaunch/XML): Documents which describe sets of ROS nodes to launch together.

[rviz](https://github.com/ros-visualization/rviz/blob/hydro-devel/default.rviz): YAML configuration files belonging to the [rviz](http://wiki.ros.org/rviz#Overview) utility.

Each one has been in use for several years in various ROS-related applications; lots of examples should be apparent in orgs like ros, ros-drivers, ros-visualization, pr2, turtlebot, husky, etc.

Thanks for your consideration!
Merge pull request #791 from mikepurvis/patch-1

Add five new extensions to XML, YAML in support of ROS usage.
Merge pull request #790 from hkdobrev/composer-lock

Add composer.lock to JSON filenames
Changed primary extension for Max

Changed primary extension for Max to .maxpat 
.mxt is a legacy file format.
Moved the Max examples to the Max folder
Merge pull request #794 from natcl/patch-1

Changed primary extension for Max
Just the extensions for now
Update samples
use JSON instead of YAML for loading samples.json
prefer JSON, but fall back to YAML if JSON isn't available
Merge pull request #806 from github/use-json-for-loading-samples

Use JSON instead of YAML for loading samples.json
require escape_utils >= 0.3.1
force escape_utils 0.3.2 on ruby < 1.9.3
Merge pull request #807 from github/update-escape_utils-dep

Require escape_utils >= 0.3.1
Bump pygments.rb to 0.5.4
2.9.9
prefer to load from languages.json if it exists
Merge pull request #809 from github/languages.json

Prefer to load from languages.json if it exists