Fixes #2725

This deletes the empty and unused Desktop assemblies from the code base.

Right now the IDE uses the Csc/Vbc host objects from the build
task by loading the task from the GAC (since the task is only
installed in the MSBuild directory otherwise). However, this breaks
using a different task for ETA tests since the GAC will always
take precedence.

This change adds the build task to the VS setup to include the
task in the IDE installation.

FxCop is currenly reporting a false positive error for calls to XmlReader.Create() in projects that compile against the .NET portable (core) framework. Suppress this error until the rule owners fix the rule to account for portable framework.

Fixes internal bugs 1169525, 1169526, 1169527

Separate factory methods for each of the projects that consumes it and a
little less copying.

...the same way we expand display classes and state machines.  If we see a
local or parameter with a transparent identifier generated/mangled name,
we should instead include the properties of its (anonymous) type in our
list of bindable symbols.

Points of interest:
1. Transparent identifiers can be chained (i.e. have transparent
identifier properties).
2. Transparent identifiers can be captured (i.e. they might be display
class fields, rather than locals or parameters).
3. Display class instance locals cannot appear within transparent
identifiers (i.e. the recursion goes in only one direction).
4. For the benefit of the debugger, we're actually using fields, rather
than properties.  As a bonus, this was more consistent with the display
class case and, therefore, easier to implement.

TODO: Make a (hopefully) similar change in VB.

we forgot to add null check before calling GetProject

Fixes #2567

Fixes #2623

This change removes all C# specific references from
MS.CA.Workspaces.CSharp.Desktop.dll.  This demonstrates the pattern by
which we could migrate the language specific MSBuild code into a shared
DLL which has no language specific dependencies.  This pattern will
allow us to delete both MS.CA.W.CSHarpDesktop and
MS.Ca.W.VisualBasic.Desktop.

Fixes #2232

Prevent crash by avoiding QualifiedName->PredefinedTypeName simplification inside QualifiedNames.

The BitArray approach wasn't meaningfully reducing complexity, so we'll
revert to an earlier approach that reduces allocations (by reusing an
existing ReadOnlyCollection<byte> as the backing data when possible).

Fixes #2549

This reverts commit cdf6029c.

In C#, if a WinForms InitializeComponent method() includes character
literal containing a unicode escape for a character that is not valid in
XML, it can cause an XML parser exception to be thrown and the WinForms
designer not to load. To work around this problem, we generate a hidden
cast expression in the IMethodXML to cast the numeric value of the
character to a System.Char.  We do this for any character that isn't a
letter or digit. The designer can process this XML correctly and load
properly.