Fixes issue#2838; this is a tweaked version of pull#2845 that
should not leak the length of the password and is more generic,
in case we run into other situations where we need
timing-attack-resistant comparisons.
- explicitly set the default of all GetBoolArg() calls
- rework getarg_test.cpp and util_tests.cpp to cover this change
- some indentation fixes
- move macdockiconhandler.h include in bitcoin.cpp to the "our headers"
section
This fixes test_bitcoin failures on openbsd reported by dhill on IRC.
On some systems rand() is a simple LCG over 2^31 and so it produces
an even-odd sequence. ApproximateBestSubset was only using the least
significant bit and so every run of the iterative solver would be the
same for some inputs, resulting in some pretty dumb decisions.
Using something other than the least significant bit would paper over
the issue but who knows what other way a system's rand() might get us
here. Instead we use an internal RNG with a period of something like
2^60 which is well behaved. This also makes it possible to make the
selection deterministic for the tests, if we wanted to implement that.
