#541 FMSLogo 7.7.0 installer doesn't abort if FMSLogo is running

[David Costanzo]

If you try to install FMSLogo while it's running, the installer is supposed to show an error message and not continue. As of the 7.7.0 installer, it continues up to the point where it fails to write to the fmslogo.exe. This is a regression from FMSLogo 7.6.0.

This is reproducible on Windows XP (32-bit) and Windows 10 (64-bit).

It's likely that I introduced a bug when upgrading the NSIS to support Unicode, which was done in FMSLogo 7.7.0.

Steps to Reproduce:
1) Install FMSLogo
2) Start FMSLogo
3) Install FMSLogo (again, while FMSLogo is running)
4) In the installer, select English as the language.

What Happens
The installer shows you the GPL and gives you options to continue with the installation.

Expected Result:
The installer prints an error like:
"Either the installer or FMSLogo is currently running.$\nThis installation cannot continue."

[David Costanzo]

Fix by [r5261]. This fix will be available in whatever version follows FMSLogo 7.7.0.

This was a regression introduced when I updated the installer to be Unicode in FMSLogo 7.7.0. The installer was still calling the ANSI "CreateMutexA" with what presumably was now a Unicode string and therefore may have been interpreted as "L" instead of "LogoForWindowsMutex". Using the WCHAR from CreateMutexW restored the desired behavior.