add support for a custom Namespace prefix
use AWS's timestamp instead of arbitrary date

also :
- cleanup the member selection
- cleanup the prefix setting
ensure data points are in chronological order
move libs
refactor the configuration options

- use optparse to read command-line options
- config now moved to a specific folder
- separate credentials from the rest of the configuration to improve
security
config update : update manual accordingly
gitignore
fix manual (grr)
Update README.md
Update README.md
Update README.md
fix markdown syntax
gitignore update
Merge pull request #1 from Samuel29/master

Work from Samuel29, much improvement to original code