fix overlapping value tracker texts by spacing them out

label height is still hard coded

Nonexisting configuration file log changed and handled.
Minor name changes and fixes.

Becasue commandline options handled in constructor, error logs dont have access to message handler. Solved.
Additionaly when MainWindow destroyed, logs messages still logged properly.

_selectPort function changed to selectListedPort
unnecessary speed word removed from baudrate option
code optimization with portIndex

ApplicationName get from PROGRAM_NAME macro in CMakeLists.txt
Default settings name get from PROGRAM_NAME macro in CMakeLists.txt

fix FindQwt script for platforms where qwt qt5 version isn't called 'qwt-qt5'

also added check for Qt version of the found qwt library

symbol setting may not exist in loaded settings file

such as at first run, don't display error in this case

make buildable with Qt version smaller then 5.5

ubuntu 14.04 ships with qt 5.2 and this is a relatively small optimisation

fix symbol show settings not loaded at startup

'toggled' is emitted for 'setChecked', 'triggered' is only emitted when user
actually clicks something

removed dependency to qtcolorwidgets library

color selection is implemented with a qpushbutton and qcolordialog

added linear index buffer to support scaled x axis

this is also an important step towards "x data" support

simplified ascii parsing, in auto num channels won't change on error #39

also if a parsing error occurs all of the line is ignored

re-implemented functions made explicit
unnecessary line deleted

leaving numChannels implementation completely to actual reader
undone commit 'numChannels common in all readers, abstracted'