doc: small doxygen update

I was merging change this every time before generation of
the doxygen developer docs (https://dev.visucore.com/bitcoin/doxygen/)
but there's no reason why it can't just be merged upstream.
Add additional data update to release-process.md

This adds https://github.com/bitcoin/bitcoin.org/pull/270 to the to-do
list for each release, avoiding future situations like
https://bitcointalk.org/index.php?topic=336042.0.
Coincontrol cleanup (e.g. add missing license)

- add missing license headers
- make compatible with Qt5
- enforce header cleanup style
- small code style cleanups
- rename Coin Control dialog into Coin Control Address Selection
- use default font for the windows labels (no monospace)
Merge pull request #3272

0e165b9 doc: small doxygen update (Wladimir J. van der Laan)
Merge pull request #3275 from Michagogo/release-process-binary-sizes

Add additional data update to release-process.md
Merge pull request #3267

0689f46 Coincontrol cleanup (e.g. add missing license) (Philip Kaufmann)