SharePoint 2013 Upgrade issues (Migration from SP2010 to 2013)

People search not working, peopleresults.aspx page does not exist and people search webparts missing

User Permissions not working becuase in 2010 user “domain\username” but 2013 user “i:0#.w|domain\username”
solution
Migrate from classic-mode to claims-based authentication in SharePoint 2013(http://technet.microsoft.com/en-us/library/gg251985.aspx)
http://social.technet.microsoft.com/Forums/sharepoint/en-US/04a5dcc0-83f8-4b44-b84c-134922902010/migration-from-sp-2010-to-2013-user-permissions-not-working?forum=sharepointadmin

/_layout/images/pdf_icon.gif missing

Branidng custom theme in SharePoint 2013
http://msdn.microsoft.com/en-us/library/office/jj927175(v=office.15).aspx
http://sharepoint.stackexchange.com/questions/87545/branding-sharepoint-foundation-2013

branding masterpage is not applied.
-> delete the file using powershell script and upload again.
$lib = $web.GetFolder(“_catalogs/masterpage”)
$file = %lib.Files[“abc.master”]
$file.Delete()

Health analyzer
Missing server side dependencies error
[MissingSetupFile] File [Features\abc.webpart] is referenced [1] times in the database[WSS-Content_xxx], but exists only under Microsoft.SharePoint.Foundation 2010 setup folder. Consider upgrading the feature/solution which contains this file to the latest version.

-> I decided to delete the feature using follow website.
http://get-spscripts.com/2011/06/diagnosing-missingsetupfile-issues-from.html