* initial work on issue #50 (from MMahlberg) concerning the "System under Design": introduced SuD

https://github.com/aim42/aim42/issues/50
Merge commit '2a7c7b8112c3804d89f7d616b2bcc0804c6d9526'
initial work on https://github.com/aim42/aim42/issues/50
removed an old image (from openclipart) - not used any longer
new image "continous improvement" (graffle diagram)
https://github.com/aim42/aim42/issues/51

Estimate in Interval, new practice.
mainly https://github.com/aim42/aim42/issues/51

* continued work on #51, corrected links and sort-order,
* renamed "determine-feature-value" pattern,
* removed duplicate entry in pattern-index
corrected arrow-direction in concepts-diagram (thx to MMahlberg for pointing out this issue)
include "fast-feedback" into pattern-index (again, thx to MMahlberg)
added sublime-workspace settings to gitignore
added image for "view-based-understanding"
reference to "fail fast"
included image to view-based understanding. looks nice, imho
corrected phase description
* some corrections to pattern index, especially "take-what-they-mean",
* assignment of several patterns was misleading
* removed TODO tag from MMahlberg
* corrected links
completed "contributing to aim42" section
typo...
* typo, again.
* Explained ACL pattern with quote from Eric Evans
added a whitepaper.
improved layout of whitepaper