Preliminary Python 2.7 Plugin Support for Sigil

Patches add preliminary support for using an already installed Python
2.7 interpreter to act as a plugin engine for Sigil
strike tag has been deprecated

replace strike tag with del tag to quite Flightcrew about deprecated
tags
fixes for minizip to play better with Cpp

add include ifdef guards and wrap include of windows.h in proper extern
"C" { }
plugin -  check for well-formed xhtml/xml

give user a chance to abort changes made by plugin if xhtml/xml to be
added/modified is not well formed
prevent plugin closing last tab and cleanups

prevent plugin closing last tab and cleanups
add python2_7 launcher folder
trying to properly commit python2_7 folder
trying once again to add new files
argh!
trying again to add python files after editing gitignore
fix for name clash in Windows with DeleteFile

changed Utility::DeleteFile to Utility::SDeleteFile
fix for missing endif in header guard
bug fixes

fixes for textEdit interpreter path and using cancel in AddPlugin
change preferences ui to min expanding

Change PreferencesWidget ui to miniumexpanding so that buttons are no
longer hidden
further namespace cleanups

use full namespace qualifier for static methods
remove last friend class use

remove last friend class use by passing in TabManager object to
PluginRunner constructor and associated fixes
fix QProcess arguments to work on Windows as well
Fix prefernces widget layouts.