Fixed URI encoding bug from java for "[]" chars in authority

See discussion at cwi-swat/rascal#498
Merge pull request #37 from DavyLandman/master

Fixed URI encoding bug from java for "[]" chars in authority
Added (de)serialization of keyword parameters with the syntax f(size=1),
for a constructor with name f and keyword parameter size with value 1.
We also had to fix a number of issues caused by the problematic
semantics of isEqual and equals and we changed the semantics of equality
between an IConstructor and an INode with the same name and same
arguments: they can not be equal anymore.
Merge branch 'master' of https://github.com/impulse-org/pdb.values into persistent-set-case-distinction