Save information about opened/closed FILE streams into the trace. This is the
first step of issue #37.

Add two new events: FileOpen and FileClose. These both contain the runtime
value of the FILE * for the stream, the offset of the null terminated filename
in the trace's data, and the offset of the null terminated mode string in the
trace's data. To support this, TraceStream has been updated to hold the offset
of the filename and mode strings. Two convenience functions have been added
to TraceThreadListener to handle the recording of stream opening and closing,
recordStreamOpen() and recordStreamClose(), and all listening points that
update the stream information have been updated to use these.

TraceProcessListener now records the initial runtime values for stdin, stdout,
and stderr, and records them into the process trace. These are restored by
ProcessTrace.

The trace format version has been bumped to 3.
Allow raw access to the process trace data.
Add stream information to ProcessState (part 2 of issue #37).

Restore stream information from the thread trace when processing FileOpen and
FileClose events.
Add a seec::cm wrapper for StreamState information. This is part three of issue #37.
Add a method to check if a memory region is at least partially initialized,
MemoryState::Region::isPartiallyInitialized(). This method also returns true if
the region is completely initialized. Clients that must check for partial, non-complete
initialization should check the result of isCompletelyInitialized().
Render FILE * values correctly. Close #37.

Add a new subclass of seec::cm::Value, seec::cm::ValueOfPointerToFILE. This is
used to represent values with type FILE *. It doesn't allow clients to access
dereferences of the pointer, or get information about the pointee, but it does
allow the client to check if the FILE * references a currently valid (open)
stream.

Update graph layout and expansion to correctly deal with ValueOfPointerToFILE.
Currently the string value is displayed, rather than rendering pointers to a
common FILE node.