Reduce logging noise
Re-enable external exposures, set pre-read flush offset to -5 secs
Allow SXCCDIOExposeCommandM25C to read less that the full requested number of lines and allow for this in post-processing, add a stub for SXCCDIOExposeCommandM26C
Bump version to 1.0.4
Merge branch 'bsx-io_v1.0.3' of github.com:simonct/CoreAstro into bsx-io_v1.0.3