Refactor the Windows MinidumpGenerator interface to get rid of the overloads when generating dumps.
All required params are now passed to the constructor and the various options are set through new methods.

BUG=N/A
TEST=Existing minidump generation tests
R=mark@chromium.org

Review URL: https://breakpad.appspot.com/1074002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1274 4c0a9323-5329-0410-9bdc-e9ce6186880e