Rewrite all file loading to use QUrl for network transparency and
being able to better handle the differences between relative and
absolute paths.

Transforming relative to absolute paths is done in two places: XMLParser
(as any HSS files loaded from there are relative to the XML file itself)
and in HSSParser::readNextStatement when reading #import instructions
(as any HSS files loaded from there are relative to the current HSS file).

However, why is HSSRequest loading XML files? This situation may not be
handled properly for relative paths…

AXRWrapper::loadFileByPath, loadXMLFile, and loadHSSFile, may take an
absolute or relative path. These are user-facing methods that may be
called by client applications. If a local, relative path is given it
will be interpreted relative to the application's current working
directory.

AXRWrapper::getFile accepts absolute paths only. If a relative path is
given to it, an error will be thrown. This is an internal method that
should not be called externally, and thus any paths passed to it should
be converted to absolute paths.

Hardcoding "file://" + path and all sorts of other hacks is very error
prone, and caused the Windows prototype not to load files at all, which
this issue also fixes.

Some files are included for testing that relative paths are loaded
properly, however due to #154 this is somewhat difficult to test
properly so there may be regressions introduced with this commit.

The AXRTestThread and AXRTestProducer classes may be broken now, but
they are such a mess that they need to be completely redone anyways.

Files now load properly on Windows!

Closes #147.
Fix debug log crash on app exit. Currently this causes destructors to
log to stdout instead of our custom logging device but we'll rearchitect
that later...
Source packaging is currently breaking CI - disable this *properly* now.
Fix .rc file for SDL app and add one for main prototype app so that the
apps will have proper icons on Windows.

I've also re-saved all the .ico files. Visual Studio 2010's resource
compiler was giving the RC2176 error when attempting to compile the
prototype and example executables. For some reason the old files were
corrupt somehow, with Visual Studio failing to display all but the
256x256 icon, showing sizes such as 48x0 in menus, as well as other
error messages.

I've saved the .ico files with Icon Composer (just as before) but this
time followed a very specific procedure:

* File -> New ICO
* Drag 1024x1024 PNG from Finder into 48x48 slot
* Drag 1024x1024 PNG from Finder into 32x32 slot
* Drag 1024x1024 PNG from Finder into 24x24 slot
* Drag 1024x1024 PNG from Finder into 16x16 slot
* Drag 1024x1024 PNG from Finder into 256x256 slot
* Save file

I believe I originally dragged the icon from Finder to the 256x256 slot,
and then from the 256x256 slot into each of the others from largest to
smallest size. Apparently the order and/or location from which icons
are dragged do make a difference in Icon Composer although inspecting a
binary diff did appear to reveal a few minor differences while the order
of the icons themselves remained the same.
Fix window title handling.
Merge branch 'master' of https://github.com/AXR/Prototype