Remove class Sleeper (obsolete)

[M. Gronle]

The class ito::Sleeper can be removed and the static methods

• sleep
• usleep
• mslepp

can be replaced by the static methods with the same name of the Qt class QThread.

ito::Sleeper has been introduced as compatibility wrapper for Qt4 and 5, since QThread::sleep…
was protected in Qt4 and is public now in Qt5.

‌

[M. Gronle]

fixes issue #156: removed the obsolete class ito::Sleeper (obsolete since Qt5)

→ <<cset 203491cc1326>>