Wiki import "Before you start" and "Recommendations" pages

Created by: seancolsen

Importing (and cleaning) the following wiki pages:

https://wiki.civicrm.org/confluence/display/CRMDOC/Before+you+start https://wiki.civicrm.org/confluence/display/CRMDOC/Recommendations

...both into: /basics/planning.md

Created by: seancolsen

Re you'll: linguistically speaking, I'd say this is a contraction, which I think is okay. There was nothing in the old style guide about contractions, and I didn't add anything to my proposed style guide about contractions. I think that if we ban contractions, lots of sentences will get pretty weird because words like "it's", "don't" will need to be expanded. And creating a sufficiently detailed style guide to specifically allow and disallow certain contractions seems a bit over the top to me. I think both you'll and you will are totally fine.