Fixes bogus assertion failure.

SocketMonitor::Cancel() does not actually unregister the socket; it
only disables the event.

When mounting had not yet finished, SocketMonitor::IsDefined() was
always false, due to the workaround at the beginning of the function
that calls SocketMonitor::Steal().  This commit drops the IsDefined()
check because it was never necessary and breaks reconnect.

nfs_destroy_context() will invoke all pending callbacks with
err==-EINTR.  In CancellableCallback::Callback(), this will invoke
NfsConnection::DeferClose(), which however is only designed to be
called from nfs_service().  In non-debug mode, this will leak memory
because nfs_close_async() is never called.

Workaround: before nfs_destroy_context(), invoke nfs_close_async() on
all pending file handles.

The method NfsConnection::CancellableCallback::Callback() will always
invoke NfsConnection::Close() on the file handle, even if the void
pointer is not a nfsfh.  This can happen if the Open() was not
successful, e.g. when the file does not exist.

Mapped to "=" in the MPD protocol.  This is the first operator,
initially supporting value matches in the MPD protocol.

Replaces the sticker_domain for Error::domain.

Call sqlite3_reset() only after a sqlite3_stmt* has been used, not
before.  Assume it is already in reusable state.

SQLite 3.7.3 is the version shipped in Debian Squeeze (oldstable);
should be old enough to be the required version.  Drop the
compatibility #ifdef.

MPD used both "album artist" and "albumartist" tags and mapped them to one tag.
This could lead to issues, if a file had both tags, causing MPD to send
a list of albumartists instead of a single one.
Since "album artist" is not a standard tag anyway and even its originators
started to use the proper alternative, its time to say goodbye!

MEM_LARGE_PAGES does not appear to work.  Instead, MEM_RESERVE appears
to be necessary.  Until I figure this out, this large pages are
disabled.