Bitcoin-Qt: fixes for using display unit from options

- extend PaymentServer with setOptionsModel() and rework initNetManager()
  to make use of that
- fix all other places in the code to use display unit from options and no
  hard-coded unit
Merge pull request #2930 from Diapolo/displayUnit

Bitcoin-Qt: fixes for using display unit from options
qt: Add comment to sorting step in refreshAddressTable
Add "mkbootstrap" script to contrib, for creating bootstrap.dat.
Merge branch 'mkbootstrap'
contrib/misc/mkbootstrap: rename to linearize.py
qt: Use GUIUtil::HtmlEscape to escape HTML

This is why we created this function. Avoids some #ifdef.
Merge pull request #2955 from laanwj/2013_08_htmlescape

qt: Use GUIUtil::HtmlEscape to escape HTML
fix help prompt
Merge pull request #2957 from Rav3nPL/patch-1

fix help prompt
fix the typo fix in linearize.py
Merge pull request #2959 from jmcorgan/fix-typo

fix the typo fix in linearize.py