Added aliases as discussed on pekim/tedious#179
Prevented overwriting types by aliases (pekim/tedious#179)
Added test for data-type aliases (pekim/tedious#179)
Added test for some known aliases (pekim/tedious#179)
Removed empty aliases and added check for aliases as requested (pekim/tedious#180). That should resolve pekim/tedious#179.
Merge pull request #180 from Hypermediaisobar-admin/adding-type-aliases

Adding type aliases