Correction runners as friends

See merge request !90

Correction runners get more responsibility for handling reconfiguration subhashes. Also, they don't get killed and replaced, but can respond to more changes, including number of frames.
Previews are overhauled, with more code moved to preview_utils and each individual preview output (name of OutputChannels change) has its own preview reduction settings.
More tests added all around.

Add compatibility with new pclayer release

See merge request !80

Add/saturation monitor

See merge request !94

Ping managed devices to check whether they're still alive

Closes #39

See merge request !92

Fix getting hostname for error messages about device servers config

See merge request !93

GH2 updates after initial HIREX test

See merge request !91

Update strixel "rows A1256" implementation to accomodate rotation

See merge request !88

2.19 compatibility (correction devices)

Closes #33 and #34

See merge request !84

Fix depends

See merge request !86

Move geometry devices, some utilities to own repositories

See merge request !82

Use multiprocessing.shared_memory instead of posixshmem

See merge request !83

Use devpi, drop calgDeps

See merge request !79

Fix import for Karabo-2.19 compatibility

See merge request !81

make responding to different number of frames faster

See merge request !64

DetectorAssembler: error in QxMy source-to-index regex
Warning system: contexts with None as waning type
GH2: no safeNDArray in writeChannel
Condition watchers: allow slots from ERROR state
Multiple devices: default to overview scene (when was this lost?)