Fixed Save As dialog
Replaced value equality with reference equality

This change is fairly dangerous.
Implemented Compile<T> for compiling the expression to a function
Compiles the VS expression for performance
Added Compile<T> method (wrapper around Compile extension)
Added simulation parameter support, GlobalExpr<T> wrapper
Fixed oversampling
Some basic, temporary stuff to make the simulation work
Merge branch 'master' of https://github.com/dsharlet/LiveSPICE