Merge pull request #41 from MichaelMahlberg/invariants_and_zombies

Invariants and zombies, sounds good!
* re-formated pattern-index (references in labels now formated manually)
* added one image
added about section

as Alex suggested - I added a simple about section with a nice admonition - and a few introductory words.
added OORP pattern book

as suggested by @feststelltaste - I added this important reference (which is an early approach to evolution, nicely done, but somewhat more focussed in scope)
minor adjustments to about and introduction
extracted "the team" into own file

so adding team members gets modular
* corrected link to software-archeology
* corrected link to 'category-crosscutting'

* the link in pattern-index was messed up
* some links to category-crosscutting were wrong (`>`missing)
corrected link to view-based-understanding
* correct link to "invariants and zombies"
* corrected reference to analysis phase in eval-goal
* added images for phases (eval and improve)
* checked phase-goals (to close https://github.com/aim42/aim42/issues/18)
add a pointer to ISO 14764 to the intro section and group reasons according to it
Merge pull request #42 from ck-innoq/intro

add a pointer to ISO 14764 to the intro section and group reasons according to it
added ISO 14764 to bibliography, inserted link in introduction. Thanx CK!