Make Pycicle work for any Project

[biddisco]

In order to use pycicle for projects other than HPX, there are some HPX specific variables/links that need to be made into options or configurable elements.

[biddisco]

• Main support that removes any HPX dependencies has been added in Allow non HPX projects to be used with pycicle #10
• Update Docs to explain new features/usage
• Add support for running builds for more than one project at a time - done in DCA pycicle support #15
• Allow project specific build settings be be taken from the project itself and not stored in the pycicle repo

[PDoakORNL]

• Each trunk should not require a project level directory under config

I made the first steps toward item 4 in #23

One question to answer is the priority of args, various levels of config from CMake.
I would propose the following priority

1. command line arguments
2. pycicle/config//.cmake
3. /pycicle_config/.cmake
4. pycicle/config//.cmake

By priority I mean if a lower priority value is found, it is not reset by later files. Right now it is generally written but the order and number of time the config .cmake files is read I'm not entirely sure of.

PycicleParams should make it easy to read the .cmake files once and have clear precedence as far as pycicle.py is concerned.