relaxed matches (regular expression like syntax)

[jhcepas]

some proposals for the relaxed matching syntax (using Perl symbols):

Find nodes where (a,b) is connected to (c,d) by one or more intermediate parent nodes:

( ((a,b))+, (c,d));

Find nodes where (a,b) and (c,d) exist in the same tree connected by any number of nodes:

( ((a,b))*, ((c,d))*);

Ideally, this should also allow us to combine with basic node searches. For instance, find nodes where (a,b) is connected to (c,d), by one or more duplication parent nodes:

( ((a,b))'+is_duplication(@) == True', (c,d));

Syntax looks ugly, I know, but once the functionality is in place we could think of a more readable method