glib: install properties before class_init finishes

Recently glib started to warn about the future deprecation of adding
interfaces after class_init, which we fixed here [1].

Now, a similar warning has started to happen for the addition of
properties, example:

(Nereid:23225): GLib-GObject-WARNING **: Attempt to add property __gtksharp_33_Banshee_Widgets_TileView::gtk-sharp-managed-instance after class was initialised

So we need to add them before class_init finishes too, and this
change makes it this way.

[1] https://github.com/mono/gtk-sharp/commit/9ff7ec8b2c6a1727f61601bd934d65a790f5adda
generator: simplify bool logic in Method class

There are two elements repeated in this expression:

(( ((A) || (B)) || (B)) && C)

We can simplify "(A || B) || B" to simply "A || B",
so the result is a bit more readable this way:

(A || B) && C
generator: drop unneeded parameter in WriteLine() call
generator: leverage framework's String.IsNullOrEmpty() call

This makes the code a bit more readable and it is a
micro-optimization.
Merge pull request #80 from knocte/master

atk: add metadata fixup to avoid crash due to ABI break
gio: update MSBuild csproj file to account for recent changes
generator: fix AssemblyName in MSBuild csproj

To be the same as what is generated via Makefiles.
generator: add reference to System.Core in the MSBuild csproj

Extension methods (such as the one we have in XmlElementExtensions.cs)
need to link to System.Runtime.CompilerServices.ExtensionAttribute
class in order to compile. In .NET 3.5, this was part of System.Core
(not mscorlib like in .NET 4.5) [1], so we need to link to it in order
to compile via MSBuild.

[1] http://msdn.microsoft.com/en-us/library/system.runtime.compilerservices.extensionattribute%28v=vs.90%29.aspx
gdk: enable Unsafe in MSBuild
gtk: reference Cairo in MSBuild csproj
glib: include recent files committed in master to the MSBuild csproj
glib: fix warning

`t` was not being used.
Merge pull request #81 from knocte/properties_class_init

glib: install properties before class_init finishes
Merge pull request #82 from knocte/cleanup

Various small cleanups in generator and glib
Merge pull request #83 from knocte/msbuild_tweaks

Various tweaks and updates to the .csproj files
MSBuild: fix the solution build (except audit and sample projects)

This commit makes it possible to build any project of the gtk-sharp.sln
from an IDE (except audit and sample projects, which require a bit more
work). This doesn't mean that AUTOTOOLS is deprecated, but just that it
is more comfortable to use an IDE when working on gtk-sharp because it
will offer better auto-completion, and will stop highlight misleading
semantic errors, from now on.