`DECLARE_COMPONENT_PROPERTY( MyComponent, "myprop", "value" )` can be
used to set properties on already declared components.

Sometimes it is useful to be able to deprecate components, i.e. to
make sure a particular job does not use a certain set of components
(e.g. a multi-threaded job should not use components that are known to
be not thread-safe).

This can now be achieved by setting the "deprecated" property in the
plugin registry:
```
  Registry::instance().addProperty( "MyTool", "deprecated", "optional message" );
```

In addition, the warning can be turned into an error using the new
`setError` method.

See merge request gaudi/Gaudi!1400

See merge request gaudi/Gaudi!1399

Closes lhcb/Gaudi#3

See merge request gaudi/Gaudi!1397

See merge request gaudi/Gaudi!1381

Closes #236

See merge request gaudi/Gaudi!1398

See merge request gaudi/Gaudi!1394

Closes #240

See merge request gaudi/Gaudi!1392

Previously the basket size configuration could only be coarsely applied to all
branches but in most real world files the size of the data in each branch varies
significantly. Setting a small value causes large branches to be packed into
individual baskets and prevents effective compression. Setting a large value
improves the compression ratio of large branches but causes excessive memory
usage.

Instead we change the parameters to only specifiy the maximum and minimum
branch size and provide a target for the number of events to pack into each
basket. We then use the first event to estimate the size of the branch.

This makes the branching very sensitive to the first event size however this
seems to work okay in practice. If needed the basket sizes could be refined
after several events to give a more precise estimate.

See merge request gaudi/Gaudi!1391

See merge request gaudi/Gaudi!1393

See merge request gaudi/Gaudi!1390

See merge request gaudi/Gaudi!1389

See merge request gaudi/Gaudi!1388

See merge request gaudi/Gaudi!1387

See merge request gaudi/Gaudi!1386

See merge request gaudi/Gaudi!1384

Create a symlink to the built Python binary modules so that they can be
imported as `Package.Module` (same as it is the case once they are
installed).

When the static function TH1::SetDefaultSumw2 had been called (passing true), `Sumw2(true)` is automatically
called by the constructor of TProfile. This is a problem because in the profiles in Gaudi::Accumulators we do
not keep track of the sum of squares of weights and consequently don't set fBinSumw2 of the TProfile, which in
turn leads to a self-inconsistent TProfile object. The "fix" is to disable sum of squares explicitly.