Menuinst

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* Disable 'quicklaunch' shortcuts for SYSTEM user (33)

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* Add license explicitly (BSD 3-clause) (26)
* Rework elevation on Windows to not use separate batch file (27)
* Improve support for non-ascii characters (27)
* Migrate to Windows KnownFolder instead of CSIDL for win > XP (27)
* support istalling as SYSTEM user on Windows (for SCCM usage) (29)
* Add Appveyor for build testing (30)
* Drop CSIDL support in favor of uniform KnownFolder usage (31)

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* keep temporary directory around, due to strange Windows race condition

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* add Windows elevation, see PR 22

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* add menuinst entry point module menuinst.main
* fixes for Windows XP

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* remove all use of root_prefix (it is always sys.prefix), and subprocess
calls to Python (which does not work on Windows XP with pythonw.exe)