used the term 'spread' as in the neuralynx software for now

works ok with RHD data

works for 64 channels now

these give reasonable output now, but it looks like we're getting the
same data on all three aux ins

works well with one and two cables on current rev board

replaced drawLine method with pixed based plot. Increases speed at the
cost of anti-aliasing.
Also centered channel number display in channel,
and set default channelHeight to 40, so that ~16 channels should fit on
a 1080p screen

got number by calibrating against reid's code - fix this some time

bandpass filter setting seem to work only when set before acquiring data for the 1st time

added setSampleRate,
setUpperBandwidth,
setLowerBandwidth
also updated getSampleRate

Removed the call to updateParameterButtons from audionode, which leads
to crash when adjusting the volume on slider.

The problem is that updateParameterButtons can't be called from any
editor that doesn't use the parameterEditors array. While this can be
fixed by just removing the call from all the processors, ideally there
would be a more robust way to check if it's used. Checking if
parameterEditors.size()==0 seems to catch it some times, but other
times seems to cause a crash. I'm not sure why it doesn't work: the
constructor for Juce Arrays specifies that numUsed should be equal to
zero for an unused Array, and parameterEditors should exist for all
editors that inherit from GenericEditor.

Fixes a bug with my previous change that would crash the program if you
tried to change the parameters of a processor without a parameterEditor.

Allows parameters to be set from saved XML and changes the
parameterEditor buttons (currently for discrete parameters only) to
reflect which parameters are currently used by selected and
non-selected channels. This fixes a problem where the buttons would
always show what the last press was rather than the current values for
the active channels (e.g. If you changed the parameters on Channel 2,
and then switched to select only Channel 1, the GUI would incorrectly
indicate that the settings for Channel 2 were active). Additionally,
allows the user to see what parameter values are used for channels not
currently selected.

- Clean up methods in GenericProcessor
- File selection now happens outside of EditorViewport
- Add mechanism for saving custom parameters for individual channels
- Settings file is automatically saved at the start of recording