A couple of fixes and many typo / consistency fixes

Hope you didn't miss me! *<:@)

Fixed Cynthia mission having broken it when I moved it (apologies) and a number of typos, grammar fixes and planet consistency fixes. A few places also have a little extra in the descriptions/bar descriptions.

Can I check before I go on with this whether there was and/or still is a policy to mark (many) unlandable planets as class A (irrespective of their space graphic)?
I can't see how any assumptions about this can be safe though as there are landable worlds that are class A and many of the the worlds I found marked as class A are clearly other things (including class M - I should note I avoided marking any as class M by marking them as O, K or L instead as I'm sure I've seen code that looks for class M planets in missions; though I can't remember if it also checked whether the planet was landable). The fact that the Class of a world also doesn't match it's graphic (it's only description) seems wrong also in case people do start depending on the class as being at least vaguely accurate...