adjust distortion scaling
improve algorithm

Change offset for a better asymmetry control, that changes the shape of
the input signal by setting the amount of distortion for the negative
values without affecting the positive values.

Calculate post gain using RMS like with polynomial drive.
lv2-examples are now pd
improve offset processing
remove -std=gnu99 flag
fix Makefile targets

Add the source
simplify processing

This commit removes the internal filters and leaves just a simple DC
blocking filter.
refactor controls

Rename Input Gain to Gain and Output Gain to Gain.
add resonance and presence filters
add tone shaping filters

This begins the work on making this plugin a more of a general
`amp-in-a-box` type of plugin. There are eight filters in total
implemented as biquad IIR filters.

Bright is a high shelf to smooth the normal response of passive guitar

Tight is a high pass filter to cut out low frequencies.

Bass, mids, treble are peaking eqs to be used with 'on board' controls.

Cab filters are low and high pass filters to mimic the response of a
add octave implementation for biquad
fix on off switch text being off center