This introduces the microdump_stackwalk binary which takes advantage
of the MicrodumpProcessor to symbolize microdumps.
Its operation is identical to the one of minidump_stackwalk.
This CL, in fact, is also refactoring most of the common bits into
stackwalk_common.
BUG=chromium:410294
R=mmandlis@chromium.org
Review URL: https://breakpad.appspot.com/4704002
git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1405 4c0a9323-5329-0410-9bdc-e9ce6186880e
