Prepare for version 1.54
Update version number of the manual.
The Unisens to EDF converter now supports also files with binary format
double, int64 or uint64.
 The spectrumanalyzer now can plot a logarithmic vertical scale.
Prepare for Qt5.
Fixed a compilation error on Mac OS using Qt 5.
Fixed a bug in the filter dialog that caused some widgets not being shown.
Code clean-up, removed some old code. Little patches here and there.
From now on, the MinGW-w64 compiler needs to be used for Windows.
Annotations tab header modified:  Filter -> Search

Search is a more typical keyword.  Removing the Filter string also frees up some space for search text.
The annot editor and annot doc was beautified.
Annot Editor:  ...has now a more complex widget
structure that allows for a better usage of space.
Also, we have shortcuts for the buttons!
Annot Doc.:  ...has a better header structure,
and I changed the default behaviour to absolute
rather then relative time.  Maybe that should be
modifiable in a separate config. file.
Changed key bindings for the annotation editor.
Now the hot keys don't clash with the ones operating
to the menu bar.
Merge pull request #1 from jusjusjus/V154

V154