Improve Run Command with environment variables containing spaces

[lifenjoiner]

Align with Win + R, for convenience.
Test example: %ProgramFiles%.

[zufuliu]

all ExpandEnvironmentStringsEx() + ExtractFirstArgument() requires similar change.

case IDC_SEARCHEXE: could use:

ExtractFirstArgument(arg1, arg1, arg2);
ExpandEnvironmentStringsEx(arg1, COUNTOF(arg1));
ExpandEnvironmentStringsEx(arg2, COUNTOF(arg2));

[zufuliu]

Committed changes as ca52161, applied similar change to metapath, kept ExpandEnvironmentStringsEx() for lpParameters as the document for SEE_MASK_DOENVSUBST says:

Expand any environment variables specified in the string given by the lpDirectory or lpFile member.

[lifenjoiner]

Great!
Careless me.