Added NumPy examples for Craig's presentation

Example 1: algorithm for finding the pairwise distances between all spheres in a
set. Multiple functions are defined and benchmarked to show how to use
NumPy to maximum advantage.

Example 2: the distance-finding algorithm is used for collision detection
Added matplotlib examples

basic_matplotlib.py shows the simple pyplot interface
presentation_graphics.py illustrates more advanced plotting with
  the object-oriented API
plot_circles.py is another example used to make a figure for
  my presentation

Removed unneeded import in NumPy/distance_validation.py
Added matplotlib examples

basic_matplotlib.py shows the simple pyplot interface
presentation_graphics.py illustrates more advanced plotting with
  the object-oriented API
plot_circles.py is another example used to make a figure for
  my presentation

Removed unneeded import in NumPy/distance_validation.py
Added SciPy signal processing examples

SciPy/linear_filters.py
Demonstration of linear filtering with SciPy

SciPy/LTI_Simulation_with_Python.py
Modeling a 1st-order LTI system with SciPy
Added SciPy signal processing examples

SciPy/linear_filters.py
Demonstration of linear filtering with SciPy

SciPy/LTI_Simulation_with_Python.py
Modeling a 1st-order LTI system with SciPy
Merge branch 'master' of github.com:cfinch/OrlandoPythonUserGroup
Merge pull request #3 from cfinch/master

Adding files for Craig's NumPy/SciPy/matplotlib presentation
Merge pull request #4 from orlandopython/master

Merge pull request #1 from westover/master
Cleaned up and commented maplotlib examples
Added license and readme and .gitignore

License and readme for my code only.
.gitignore is for everyone.
Cleaned up and documented NumPy examples
Cleaned up SciPy linear system examples
Cleaned up SciPy LTI example and improved README

- Added URL for the slides to the README
- Renamed LTI system example script to match other files
- Cleaned up comments and plots in LTI system example
Delete LICENSE.txt from my subdirectory

Avoid confusion-root directory has Apache license
Merge pull request #5 from cfinch/master

Cleaned up NumPy/SciPy/matplotiib demos
Merge pull request #2 from westover/master

Sync with westover repo