Altered SkInstCnt to print out atexit

This doesn't buy us much in terms of eliminating "leaks" but does remove the ugliness in gmmain.cpp

BEFORE

  Leaked SkRefCnt: 267
     Leaked SkFlattenable: 233
     Leaked SkWeakRefCnt: 1
         Leaked SkTypeface: 1
     Leaked GrFontScaler: 4
     Leaked GrKey: 4
     Leaked SkPDFObject: 22
         Leaked SkPDFDict: 2
         Leaked SkPDFArray: 2
         Leaked SkPDFName: 8
         Leaked SkPDFInt: 10
     Leaked SkStream: 1
         Leaked SkMemoryStream: 1
     Leaked SkData: 2

AFTER

  Leaked SkRefCnt: 266
     Leaked SkFlattenable: 232
     Leaked SkWeakRefCnt: 1
         Leaked SkTypeface: 1
     Leaked GrFontScaler: 4
     Leaked GrKey: 4
     Leaked SkPDFObject: 22
         Leaked SkPDFDict: 2
         Leaked SkPDFArray: 2
         Leaked SkPDFName: 8
         Leaked SkPDFInt: 10
     Leaked SkStream: 1
         Leaked SkMemoryStream: 1
     Leaked SkData: 2

[bsalomon, 2012-06-26 22:04:22]

Awesome! LGTM.

[robertphillips, 2012-06-27 19:52:35]

committed as r4377