Generic changes:

- Genuinely unused variables (-Wunused-variable): delete
  them. Sometimes add a comment if the variable is for an extension of
  the code that isn't done yet.

- Variables that became unused due to commented-out
  code (-Wunused-variable): comment out their definitions. Dirty, but
  that's because commenting out code instead of deleting it is
  dirty.

  Many of these are due to commented-out printlines that should have
  been log messages that only get emitted at high verbosity level.

Specific changes:

- SpikeObject.cpp (-Wunused-value): move initialization of loop
  variable into first for loop clause to silence the warning.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

Rearrange member initialization in constructors to silence GCC
-Wreorder warnings (-Wreorder is enabled by -Wall).

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

These should only be defined once. Instead of making them private to
ProcessorList, define them at global scope in ProcessorList.cpp, so
ProcessorListItem can use them too.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

Uses the parameters array to create XML data for parameter settings on
each channel when saving.

This only works for processors that use the parameters array, though I
updated LFP and Signal Generator to update that in parallel (LFP seems
to have an unrelated bug in dealing with channels that is causing some
problems). Eventually, all parameters should be used in the parameters
array, since it opens up a lot of possible holes when using default
values (they need to be specified twice), and once loading is
implemented. I've fixed some of the problems with parameters, so this
should be easier to do.

As part of this, I also fixed the implementation of
addParameterEditors. The old way of implementing a custom parameter
editor was to rewrite the virtual function, but because it was called
in the constructor, this didn't work (constructors use the type of the
parent). Instead, all editors now also pass a bool
"useDefaultParameterEditors" which is used by addParameterEditors() to
determine whether to do anything. I think this is the best way to do
it. It's initialized to default as true, though I had some trouble with
it implicitly taking the argument and so had to add true to most of the
editor functions (which is probably good practice anyway).

I also fixed some of the functions for generic processor to get
parameter index and parameter name.

Obviously, this is of considerable less use without functions for
loading parameters, but I figured it'd be better to make available for
testing with just the loading in case the changes to Parameters broke
anything I missed.

Added typeface initialization to CustomLookAndFeel, and implemented
getTypefaceForFont().

Fonts can now be created using a more centralized method, by calling the
Font(String("Typeface Name"), fontHeight, Font::style) constructor.  Names for
the typefaces ("Default Light", "Paragraph") should be regarded as tentative.

There's also simpler code to do the same thing that should be uncommented after
the 2.0 update (it uses HashMap, which is not currently in our library code,
even though it's in the 1.53 docs.)

Before, EditorViewport would start accessing arrays on keypresses (specifically
the arrow keys) even when there were no editors.  This adds an extra check to
prevent this.

VS throws errors in several locations about ambigious type casting.
Fixed by removing the ambiguities and casting things to double.