[FIX] Fixing warning in mason_variator.cpp.
Merge pull request #242 from holtgrewe/fix/mason_variator_warning

[FIX] Fixing warning in mason_variator.cpp.
[FIX] added swap for iterator proxy which typically is passed as a const-ref (this case wasn't covered by std::swap)
[FIX] added index test for packed strings
[FIX] unhided Rooted iterator of packed string
[FIX] once for all fixed CompareType<> for proxies
[FIX] added a generic assign() and operator= for StringSet
[FIX] enhanced index cross-compare test to compare the same index with different string types
[FIX] added assign, operator==, operator!= for StringSets
[FIX] fixed copy c’tors for string set
[FIX] revert to old behavior of Owner-StringSet’s appendValue()
[FIX] fixed uninitialized warning
[FIX] fixed uninitialized warning (cont’d)
Merge pull request #244 from weese/feature/fix-packed-string-swap

[FIX] fixed packed string indices and swap() for deref'ed packed string iterators
[FIX] Packed String: overloaded open() and save()
Merge pull request #245 from esiragusa/feature/packed_open_save

Overloaded open() and save() for Packed Strings
Merge branch 'develop' of https://github.com/seqan/seqan into feature/developGappedIndex
Stree Interface for gapped Index + a simple test