fixed the issue #13 about swarm requiring a CUDA device on tasks that
doesn't require a GPU
Accessor methods for ensemble, body, systems and others.only fundamental accesors are covered.
loading and saving for config and ensemble is exposed to python. access position
and velocity as lists.
Python module is now completely optional in the build
trying to debug memory mapping errors using strerror
Found a serious GPU memory leak
print the device information only once
fixing MVS testing
Allow ensembles with number of bodies larger than 10.
Adding accuracy integration config files and cleaning up the old ones.
Merge in updated tutorials.   Made make test query GPU and separate make test-cpu that does not.  Ideally, would have make test know which calls need the gpu.
Various updates to integrators
Merge pull request #15 from eford/master

Updated tutorials; Some minor updates to integrators; Preliminary swarm test-cpu
 take Eric's approach to init_cuda at test
Fixed the automatic selection of Chunk Size
Merge branch 'master' of github.com:salehqt/swarm
Added GravitationLargeN class (untested);
Attempted optimizations of Gravitation (untested)
Merged some local changes
Unundoing things confused by git
Added untested GravitationMediumN