Copied the checkmark icon into the Kopitiam plugin

The org.eclipse.ui.editors.markerAnnotationSpecification extension point
doesn't seem to support foreign resource references, unfortunately
Re-enabled support for interrupting Coq in the Java editor
Made JavaProofInitialisationRunner behave more like InitialiseCoqRunner

Some of the initialisation code, like the load path configuration, should
probably move to a common base class in the future
Added experimental support for finding a method's program variables

Although it's not hooked up to anything yet, this is the first step towards
making the specification logic less intimidating: with this information, it
should be possible to (for example) automatically replace 'this.foo' with
'"this"/V · `"foo"'
Expose CoqCommand stacks through the CoqTopEditorContainer trait
Removed the old Coq parser code

The model will take over the code folding implementation over the next few
commits. The VernacularReserved trait survives for now, although it's
become a plain object
Expose text information through the ICoqScriptElement trait

ICoqScriptGroups now have lengths and offsets derived from those of their
children
Reimplemented the code folding support on top of the Coq model

When the working copy stuff is implemented, this will work properly: for
now, though, the folding just gets hopelessly out of sync when the user
makes changes to the file
Moved some more of the Coq editor helpers into CoqEditorAssistants.scala
Added a MenuManager to the Model Explorer tree viewer

This will probably be removed when the Model Explorer is merged into the
Project Explorer, but -- until then -- it's very useful for testing
operations on model objects
Don't use case classes in the implementation of the Coq model

Using case classes rules out class-to-class inheritance, which in turn
interferes with the upcoming support for working copies
Added a trait for representing temporary working copies of ICoqVernacFiles

An implementation of this trait, along with a small supporting change to
ICoqVernacFile, will arrive shortly
Added an implementation of the new IDetachedCoqVernacFile trait

This seems to work! I'm sure something will go wrong when I try to hook it
up to the Coq editor, though
Use an IDetachedCoqVernacFile to provide code folding and outline support
Added a Java class for calling native Windows console functions

These functions should be enough to (finally) add support for interrupts on
Windows
Added a native code library exposing Windows console functions to the JVM
Added a prebuilt copy of the Windows console library to the Coqoon plugin
Added support for sending interrupts on Windows

I've never had cause to use either the native Windows console functions or
Java runtime introspection before; I hope not to have to do so again!
Added more safety checks to the Windows interrupt generation code
Clear the Windows "ignore Ctrl+C" flag after interrupting coqtop

This flag is inherited by child processes, so -- prior to this commit --
only processes created before the first interrupt would be interruptible