"CSC : fatal error CS1647: An expression is too long or complex to compile"
when building auto-generated code

This fixes issue 61.

an output before flushing.

Fixes issue 64.

copying bytes.  Should be used very cautiously as modifications to buffers may result
in unexpected behavior.

Added CodedInputStream.Position to return the current input stream position

Issue #43: Fix to correct identical 'umbrella_classname' options from trying to write to the same filename.

Collision with known MSBuild property ProjectType was causing errors, renamed to EnvironmentProjectType

Removing uses of Enum to IConvertible from CodedIOStreams,
Removed MessageStreamIterator.FromFile on non-client profiles,
Removed use of Path.GetFileName,
Removed uses of Converter<T1, T2> delegate,
Removed Guid/DispId options from test protos

Working to reduce number of conditional complication directives, and migrate towards feature-based condtions rather than platform-based

retooled MessageStreamIterator.cs to use safer/less complicated reflection.

Add generated_code_attributes option, defaulted to false to generate the CompilerGeneratedAttribute and GeneratedCodeAttribute attributes

variations (WP).  Changes are primarily superficial since they are to support
the Serialization assembly and unit tests compiling in the CF which has not
been done before.