Behavior of floor, ceil is surprising

[ajkeller34]

floor and ceil pretend the units aren't there. Not sure why I did it this way, but I think this warrants reconsideration:

julia> 20u"µm"/(110u"nm")
0.18181818181818182 nm^-1 μm

julia> floor(ans)
0.0 nm^-1 µm

julia> Int(ans)
0

... which is different from the expected answer of 181. My inclination is to define floor and ceil only for dimensionless quantities and have them convert to a unitless number first.

[giordano]

Also isinteger really depends on the actual units and can give unexpected result for non simplified quantities:

julia> isinteger(1u"m" / 10u"mm")
false

julia> isinteger(uconvert(NoUnits, 1u"m" / 10u"mm"))
true

[ajkeller34]

trunc and round also had the same problems, but I think the latest patch should fix these issues.