Better handling for opening 64-bit applications

[amervitz]

It is more difficult than it should be to open 64-bit applications using this extension. There is a workaround mentioned in #45, but it would be better if there was an option in the settings UI that let you indicate whether the command to execute should use the 64-bit version of the command instead of the default 32-bit version that gets opened (because Visual Studio is itself 32-bit).

In my situation, I wanted to open the 64-bit version of PowerShell ISE, and had to use the command %windir%\sysnative\WindowsPowerShell\v1.0\PowerShell_ISE.exe instead of using the actual path of %windir%\system32\WindowsPowerShell\v1.0\PowerShell_ISE.exe that's seen when looking at the shortcut properties for PowerShell ISE.

[doggy8088]

@madskristensen Is this possible to open a 64-bit cmd.exe from this extension?