Add Apache-2.0 license.

Per request of Alex Alexander.
Merge branch 'license'
Improve indentation style consistency.
Parse a --colors flag.
Update README.rst

I'm not actually sure whether it's typo or not. Feel free to reject this change.
Merge pull request #4 from krieiter/patch-1

Update README.rst
Add CMake error on OSX.

It is not currently supported.
Add note in README that OSX is not supported.
Don't use namespace std. It makes things too confusing.
Fix the formatting to use tabs instead of spaces, easier to read this way.
No using namespace std.

Bad form, as Hook would say.
Add support for colors.

Colors are added for terminals that have 256 color support when the
--colors flag is enabled.  The background colors are varied with different color
maps derived from their matplotlib versions.  The foreground color is a
contrasting black or white.
Add instructions for color support in the README.
Mac OS X support and BSD function stubs

Reorder the functions, begin OS X specific functions
Load averages and Memory usage now works on OSX (I hope the calculations are correct)
Minor edits
Finish OSX support - Fixes CPU usage
Merge branch 'colors'

Add support for colored output.
Merge remote-tracking branch 'Justastic/master' #1, #2, #5

Add support for Mac OSX from Justastic.  Refactors the code from Justastic so it
works with the Linux code and so it also works for the new colors support.

Still need to test on OSX.

Conflicts:
	tmux-mem-cpu-load.cpp
Output error on graph_lines < 1.  Issue #3.
Use EXIT_SUCCESS/EXIT_FAILURE.
Output error on status interval < 1.
Add tests.