Added node specific constant force

[ansue1234]

• Added nonUniformConstantForce class to apply constant force at a node in a limb
• Added various bash files to simplify compilation running different examples and running custom robots

[QuantuMope]

I would say to remove the added shell scripts. They don't seem useful other than the very first compile, which after that, you'd want to solely use dismech.sh and make changes from within robotDescription.cpp instead of in other git tracked files.

For the nonUniformConstantForce class. First, we can rename this to nodeConstantForce since nonUniform is an umbrella term for other types of force applications.

Second, how does the code run if you feed as input nodes of limbs that have been attached to existing joints. Such nodes actual refer to the joint node that exists in the original limb the joint was created on. Not handling this properly sounds like it would lead to bugs to me. Try it out. What I expect to see is the force doesn't do anything at all in these scenarios.

[QuantuMope]

Looking at nonConstantForce.cpp, I see a triple nested for loop for conducting logic that can just be done once at initialization. This should be optimized.

Function add_force_to_limb_node can be changed to camel case: addForceToLimbNode.

I am still a proponent of removing all the shell scripts and customBot.cpp. Having the user copy from a preexisting example forces them to become familiar with the API.