It sets the max number of threads to use for a parallel job.
This is different that the number of total threads, since monero
binaries typically start a lot of them.
^C while in manual refresh will cancel the refresh, since that's
often an annoying thing to have to wait for. Also, a manual refresh
command will interrupt any running background refresh and take
over, rather than wait for the background refresh to be done, and
look to be hanging.
There are various locale related bugs in various versions of boost,
where exceptions are thrown in boost::filesystem APIs when the
current locale is not to boost's liking. It's not clear what "not
to boost's liking" means in detail, though "en" and "en_US.UTF-8"
are not to its liking.
Fix it by running a test function that's known to throw in such
a case, and resetting LANG and LC_ALL to C if an exception is
thrown. In simplewallet, the locale is queried before that so the
correct translations will still be used.