In the shell sample don't print the result of executing a script, only
evaluating expressions.

Fixed issue when building samples on Windows using a shared V8
library.  Added visibility option on Linux build which makes the
generated library 18% smaller.

Changed build system to accept multiple build modes in one build and
generate seperate objects, libraries and executables for each mode.

Removed deferred negation optimization (a * -b => -(a * b)) since this
visibly changes operand conversion order.

Improved parsing performance by introducing stack guard in preparsing.
Without a stack guard preparsing always bails out with stack overflow.


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16 ce2b1a6d-e550-0410-aec6-3dcde31c8c00