RPC command getmininginfo showing right genproclimit
build: improve missing boost error reporting
doc: Add note about memory reqs for compilation
qt: Don't require db_cxx.h when wallet disabled

Fix #3978.
[Qt] small cleanup of coincontroldialog

- use a little more Qt-style
- check for NULL pointers first and return in updateView()
- small space and formating changes
Merge pull request #3991

d34b958 [Qt] small cleanup of coincontroldialog (Philip Kaufmann)
Merge pull request #3986

65adc3a qt: Don't require db_cxx.h when wallet disabled (Wladimir J. van der Laan)
4babd08 doc: Add note about memory reqs for compilation (Wladimir J. van der Laan)
25333a2 build: improve missing boost error reporting (Wladimir J. van der Laan)
Merge pull request #3931

f61287c RPC command getmininginfo showing right genproclimit (Isidoro Ghezzi)