* calcuculate curve path only when data has changed
* calculate spectrum analyzer only if signal input
* code clean up / coding conventions
* changes according coding guidelines/performance improvements in spectrum analyser/curves painting
* minor changes/white spaces
* change init order
* connect analyze view to gui->mainWindow()->periodicUpdate()
* consolidate some functions (d.r.y.)
* minor syntax changes
* fixes a right mouse button bug
* correct steepness of flanks in high and low pass filters
* Whitespaces
