Add skip checksum advanced option

[boktai1000]

Unfortunately, some patches aren't created properly and still work - and as an advanced option it would be nice to allow the patcher to force continue as it is expected to apply the patch even though the creator did something incorrectly. Perhaps hide the option, make it an advanced option or something like that. Example below.

Error occurred while patching
Details: target window checksum mismatch (code -17712)

[kotcrab]

I don't think it's a problem with the patch, rather you're trying to apply it to a different source file. Still, I guess it's true it might work for some cases. We can add it similar as they did here. That is: try to patch as usual, if that fails with checksum error then show some option/button to retry with checksum disabled.