The spectural analysis was using a rectangle window, leading to high spectural leakage.
This pull request uses the Blackman-Harris window to give a display more representative of the audio.
* redesign of EQ plugin
* correct some symbols
* set pixelPerUnitHeight to float
* change textcolor of inactive handles to white
* revert changes in styles.css
* change grid color/adjust Fontsize of info box / change analizing color
* range changed (20 - 20000 Hz) / display width increased
* Update the EQ faders and remove unused files
* Increase transparency of the graph
* corrects the filter fader peak
* makes fader peak display more useful
* Implement @zapashcanon's suggestions
* 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
