Fix footprint library file extension bug in CvPcb and Pcbnew due to s-expression changes, fixes lp:1064593.

All: fix some Doxygen warnings

Other minor fixes.

Code cleaning, minor fixes and minor coding style fixes. wxWidgets 2.9.4 compatibility fix( deprecated function MakeModal )

 fix a compil warning.
CvPcb: fix regressions :
 Shows now a void field instead of the dummy footprint name $nonane (whenthere is  no footprint selected in netlist).
 The active footprint selection changes only if a new component is selected from the component file,
 and does not change just when the next component is automatically selected, after a footprint selection.
 Speed up delete association and auto associe.

Other scaling factors (MILS_TO_IU_SCALING_FACTOR and DECIMILS_TO_IU_SCALING_FACTOR)
also defined only in convert_to_biu.h.
Allows different scaling value for Gerbview.
Needs more tests.

// This provides better project control over rounding to int from double
// than wxRound() did.  This scheme provides better logging in Debug builds
// and it provides for compile time calculation of constants.


#include <stdio.h>
#include <assert.h>
#include <limits.h>

//-----<KiROUND KIT>------------------------------------------------------------

/**
 * KiROUND
 * rounds a floating point number to an int using
 * "round halfway cases away from zero".
 * In Debug build an assert fires if will not fit into an int.
 */

#if defined( DEBUG )

// DEBUG: a macro to capture line and file, then calls this inline

static inline int KiRound( double v, int line, const char* filename )
{
    v = v < 0 ? v - 0.5 : v + 0.5;
    if( v > INT_MAX + 0.5 )
    {
        printf( "%s: in file %s on line %d, val: %.16g too ' > 0 ' for int\n", __FUNCTION__, filename, line, v );
    }
    else if( v < INT_MIN - 0.5 )
    {
        printf( "%s: in file %s on line %d, val: %.16g too ' < 0 ' for int\n", __FUNCTION__, filename, line, v );
    }
    return int( v );
}

#define KiROUND( v )    KiRound( v, __LINE__, __FILE__ )

#else

// RELEASE: a macro so compile can pre-compute constants.

#define KiROUND( v )  int( (v) < 0 ? (v) - 0.5 : (v) + 0.5 )

#endif


//-----</KiROUND KIT>-----------------------------------------------------------

// Only a macro is compile time calculated, an inline function causes a static constructor
// in a situation like this.
// Therefore the Release build is best done with a MACRO not an inline function.
int Computed = KiROUND( 14.3 * 8 );


int main( int argc, char** argv )
{
    for( double d = double(INT_MAX)-1;  d < double(INT_MAX)+8;  d += 2.0 )
    {
        int i = KiROUND( d );

        printf( "t: %d  %.16g\n", i, d );
    }

    return 0;
}

If enable in preference menu, allow the pan with drag mouse with middle button down.
both unlimited and limited pan is allowed.

Enhancements in AddMenuItem (that accepts now a menu type)
Partial use of the Edwin van den Oetelaar's patch (patch not fully working or correct)

* All objects derived from EDA_ITEM now have consistent hit test method
  definitions.
* Remove double function calls from all classes derived from SCH_ITEM.
* Lots of Doxygen comment fixes.

All: added a standard exit dialog called by int DisplayExitDialog( wxWindow* aParent, const wxString& aMessage )
Called when closing pcbnew, cvpcb and eeschema.
Minor code cleaning: remove duplicate or not used strings (mainly file extensions and wildcards)

Code cleaning and other minor fixes.

CvPcb: serious code cleaning. More comments. Remove useless files and some files renamed with a better name.

Pcbnew: Added: modview. This footprint viewer frame which has the same purpose as Viewlib in Eeschema.
this viewer is built using the new  FOOTPRINT_VIEWER_FRAME class.

Also commit updated icnos from Fabrizio.

compile base_screen.cpp separately for {pcbnew,cvpcb} and eeschema, so we can diverge internal units at compile time, not runtime