Keep the working directory (and umask) inherited from
the parent. Otherwise, it's impossible to control
the working directory of the daemon (from systemd, for
example).
Furthermoer, bitmonerod attempts to create logging directories and files
*in current working directory*. This fails due to permission denied and
generates a (caught, nonfatal) exception. Below is the strace with this
patch applied (so, no `chdir("/")`), showing successful opens at `log/`
relative path. Without this patch they fail (sorry, didn't save the
trace).
```
28911 getcwd("/.../bitmonero", 128) = 25
28911 stat64("/var/lib/bitmonero/.bitmonero", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
28911 stat64("/etc/bitmonerod.conf", {st_mode=S_IFREG|0644, st_size=244, ...}) = 0
28911 open("/etc/bitmonerod.conf", O_RDONLY|O_LARGEFILE) = 3
28911 open("/var/log/bitmonero/bitmonero.log", O_WRONLY|O_CREAT|O_APPEND|O_LARGEFILE, 0666) = 3
28911 stat64("log", {st_mode=S_IFDIR|0700, st_size=4096, ...}) = 0
28911 stat64("log/dbg", {st_mode=S_IFDIR|0700, st_size=4096, ...}) = 0
28911 open("log/dbg/main.log", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 4
```
The reasoning of chdir("/") in order to prevent the daemon from holding
a filesystem in busy state is not compelling at all: the choice of
working directory for the daemon is the user's business not the
daemon's.
When an exception happens while reading the config file, we need
to print the error, as the logging system isn't initialized yet,
so the generic catch will not print anything.
Fee can now be multiplied by 2 or 3, if users want to give
priority to their transactions. There are only three levels
to avoid too much fingerprinting. Default is 1 (minimum fee).
The default multiplier can be set by "set fee-multiplier X".
The former was a faulty "fix" for gmtime_r not existing on Windows. The latter is needed only for dynamic builds, and is not included with msys2, which ends up fine because Windows is only built static at this time.
