CO: I-70 Denver tunneling changes

[rickmastfan67]

<< NOTE: This will also effect US-6 & US-85 for first 3 points listed >>

275B -> Small location adjustment needed (also effects CO-265)
275C -> either a) adjust to new mainline and mark as *275C, or b) completely remove
276A -> Needs to be recentered on the new mainline
276B -> Needs to be recentered on the new mainline (also effects CO-2)
277 / 277A -> Merge together @ Holly Street as 277
278 -> Small location adjustment needed (also effects CO-35)

[the_spui_ninja]

I'll get these in next time I do a highway update.