remove freeze()
turn off jshint newcap
forbid the use of `new` for all types but structs
add forbidNewOperator and errs utils
relaxed `Obj.is()` to accept more object types
add isType() util
make maybe combinator idempotent
make list(T) really idempotent
make tuple(Ts) really idempotent
make struct(T) really idempotent
make func() idempotent
v0.0.11

- forbid the use of `new` for all types but structs, fix #8
- make maybe combinator idempotent, fix #9
- make maybe(T) really idempotent
- make list(T) really idempotent, fix #11
- make struct(T) really idempotent, fix #12
- make tuple(Ts) really idempotent, fix #13
- make union(Ts) really idempotent, fix #14
- export fail(), fix #15
- more tests on Dat primitive type, fix #18
- create constants for string messages, fix #16
- more tests on Re primitive type, fix #17
- make func() idempotent, fix #19
- relaxed `Obj.is()` to accept more object types
- turn off jshint newcap
- remove `freeze()` function