clean up tests; stub for dirty test
implement basic dirty test
implement isDirty with per-slice tracking

Basic tests are in place.
extend slice dirtyness test
region features: use setCoordinateOffset
hdf5 read/write of compressed array
implement BA::Array::writeHDF5, needs refactoring
progress on HDF5 r/w
extend r/w test for CompressedArray
first round of refactoring: hdf5 read/write
hdf5: refactoring
implement r/w of min/max values per block
fix unittest
hdf5 read/write of BW::Array complete
attempt to debug failing tests on travis
attempt to fix unittests for hdf5 < 1.8.7
travis: build in parallel
compatibility with hdf5 1.8.4
python: export BW::Array::readHDF5()
clean up: bw/compressedarray.h