Merge pull request #21 from michalt/semilinear

New representation of semilinear sets
Merge branch 'semilinear' of https://github.com/michalt/newton
Merge pull request #22 from michalt/semilinear

Improvements to semilinear sets
Merge branch 'master' of https://github.com/mschlund/newton
Merge pull request #23 from michalt/semilinear

Minor change to linear sets
Merge branch 'master' of https://github.com/mschlund/newton
minor corrections, added check for zero in IsCovered
new test-grammar for slsets
unique_vmap: keep a pool of allocated vectors