fix phase offset handling during sequence extraction

Closes #447.
add additional test case for phase offset
Merge pull request #448 from satta/phases

fix phase offsets for sequence extraction
add some scripts
cosmetics, review TODO/XXX add DW label to them
add condenser testdata
fix and improvement for intset

searching for a number > as the largest in the set resulted in an error.
this is not as intended, it should return the number of elements in that
case.
refactoring addition of new method

this adds a new filtering aproach to the hit finding in the compression
phase of condenser