Move the body of the usage function directly to the body of member function
datrw::imseedstream::help()

Place this code in a separate compilation unit.

- pass consistency check values to reading functions
- provide information regarding Mxm1 value which is used to check for data
  value continuity

Let MiniSEEDRecord store consistency check control flags in its own member
data.

- pass flags to inner reading function
- note changes in file headers

Read format modifiers and set flags for consistency checks appropriately.

Merge branch 'master' into 25-libdatrwxx-miniseed-consistency-checks

hide

  typedef typename aff::Series<T> Tinseries;

from compiler, because Tinseries is not used. The declaration itself however
might be useful as a reminder of which type the expected series container
should be.

Implement structures to hold control flags for consistency checks.

The only way to properly distinguish between references to the namespace and
the module documentation is by a prefix group_ for the group keyword.