update release note for 0.4rc3

tortoise: register overlay and context menu as approved extensions some users need this for the TortoiseHg extensions to work in Explorer.

about: Make logo transparent The old 92x50 png was taken from the homepage, and has a white background. The new png has transparency, which gives a nicer look for the application logo in the about dialog. In addition to this, the about dialog now has a separate 32x32 icon, which looks nicer than a down-scaled version of the 92x50 image.

thgconfig: disable Apply button on startup

cmenu: create the .hgignore file when initializing repo mainly to workaround Explorer's problem in creating files with name that start with a dot.

hggtk/commit: use internal dialog on empty tortoisehg.commit this allows user to override system setting more easily, i.e. without having to spell out 'internal' explicitly.

merge with peso

icons: Add 32x32 images to ICO files This effectively updates the icons seen when you alt-tab through applications on Windows. The 32x32 images are simply a sampling of the vector images.

icons: Add vector images for icons Vector images allow scaling to arbitrary sizes without blocking artefacts. They are sources for the fixed resolution images in ICO files. The ICO files may be hand edited at lower resolutions to increase contrast.

hgtk: fix traceback when running in non-repo directories