Implement modifiers

[ngoov]

From PR #47

modifiers
Modifiers are functions that take input and send output and then we can apply with other closes.

modifiers ❤️ filters
for example just with one DateInYear modifier you can use all filters:
mydate:year=1989 mydate:year!=1989 mydate:yearContains=9 mydate:year>9 ...

modifiers ❤️ select
for example juste with one DateInYear modifier you can use all filters:
select=name:uppercase,color:stringtohex,amount:percent

In a future release, modifiers could be chained too like that:
mydate:year:last(2)=89 to take only last 2 digits of year