#163 IfNot support for LogicLib

[Message]

The ${Unless} statement can be very confusing for new users, especially because it can be combined with ${ElseIf} and ${EndIf}. It is a rather counter-intuitive term, and since it has been asked before (see forums) I suggest we include support for IfNot to LogicLib.nsh.

I have attached the v2.33 LogicLib.nsh, with the added IfNot defines and updated documentation. To make http://nsis.sourceforge.net/LogicLib match, use the following wiki code:

<highlight-nsis>If|IfNot|Unless..{ElseIf|ElseIfNot|ElseUnless}..[Else]..EndIf|EndUnless</highlight-nsis>
Conditionally executes a block of statements, depending on the value of an expression. IfNot and Unless are equivalent and interchangeable.

<highlight-nsis>AndIf|AndIfNot|AndUnless|OrIf|OrIfNot|OrUnless</highlight-nsis>
Adds any number of extra conditions to If, IfNot, Unless, ElseIf, ElseIfNot and ElseUnless statements.

[Message]

LogicLib header file from v2.33, with added IfNot support.

[Amir Szekely]

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Thanks, applied.

[Message]

LogicLib header file from v2.34, with clearer Usage comments.

[Message]

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I made a minor change to the Usage comments for clarity's sake: "IfNot and Unless are equivalent and interchangeable, as are ElseIfNot and ElseUnless."

No other additions, I left the version number unchanged. New nsh attached.
File Added: LogicLib.nsh

[Amir Szekely]

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Thanks.