Added derived units

Added many more derived units for various quantities such as length, mass, time, substance, volume, area, current, luminous, and many more. 

Note that this also shows updates from my previous pull request as it has not been merged with nourani:master yet. Relevant changes are in  731bc3ebf43e1d8dff0379b2bb088e6f54a38305 and 45d95b2105f7c9be80ad5d5628bf7f0b014620e2.