Expose main window object to javascript

Add a new magic C++ interface object, application, to the javascript
root context which controls the main window.
Merge branch 'develop' of github.com:BitShares/qt_wallet into develop
Add MainWindow::hideWindow

It hides the window.
Fix crashes on invalid URLs
Unicode-safe handling of paths during wallet import/export
Update htdocs.qrc
Fix intermittent crash during database open at client startup in wallet GUI when boost::filesystem::path call is made from bitshares thread. To solve this problem, we must initialize boost filesystem global variables with the std::locale in the main function prior to making any boost path calls.
The code that checks for updates eventually leads to a crash if the program is left unattended, because it checks every 20 minutes for updates, pops up a message box that there's an update (assuming there is one), then goes into a message loop waiting for a reply to the message box. Then 20 minutes later, another update check is performed, etc. Eventually this leads to a stack overflow (within a day in the debug version of the application). This has probably been the cause of a lot of the crash reports we've been receiving that we couldn't interpret. As a quick workaround, I've upped the check time from every 20 minutes to once a day. This needs to be fixed so that we won't check for another update while waiting for a response from user to a previous notification. Also, I think it would be better if we didn't actually prompt the user, but just showed some kind of status message that notifies about the update and the user could click on it if they want to update, so that this notification is less intrusive.
Shut down logging prior to exiting the GUI client to prevent intermittent crashes in Wallet GUI during shutdown (this corresponds to a similar change that was already made previously in the bitshares command-line client).
Merge branch 'master' into develop
Improved version of 23241c0bbd7f9ff727a935c1b936486a28d3887d
Merge branch 'develop' of github.com:BitShares/qt_wallet into develop

Conflicts:
	MainWindow.cpp
Delete ClientWrapper before shutdown, which allows all of the async tasks in bts::client, bts::net, etc. to shutdown cleanly (fixes crashes & asserts at shutdown)
Updates to shutdown procedure. It still doesn't work right, but it's better.
Detonate implosion grenade as soon as client is destroyed.

Screw you, sleeping threads! I keel you! Hahahahaaaa!
Fix spurious crash detection
Revert exit call and cleanup shutdown of bitshares client so that GUI shuts down properly.
Avoid capturing a smart pointer to the wallet in a lambda owned by the wallet, which was preventing it from being garbage collected.
Remove some old fc logfile managing code inherited from keyhotee and no longer useful.
Enable large address space for 32-bit windows builds
Log that we are shutting down logging.