Automation: AudacityCommand

This is a squash of 50 commits.

This merges the capabilities of BatchCommands and Effects using a new
AudacityCommand class.  AudacityCommand provides one function to specify the
parameters, and then we leverage that one function in automation, whether by chains,
mod-script-pipe or (future) Nyquist.

- Now have AudacityCommand which is using the same mechanism as Effect
- Has configurable parameters
- Has data-entry GUI (built using shuttle GUI)
- Registers with PluginManager.
- Menu commands now provided in chains, and to python batch.
   - Tested with Zoom Toggle.

- ShuttleParams now can set, get, set defaults, validate and specify
the parameters.
- Bugfix: Don't overwrite values with defaults first time out.
- Add DefineParams function for all built-in effects.
- Extend CommandContext to carry output channels for results.

We abuse EffectsManager.  It handles both Effects and
AudacityCommands now.  In time an Effect should become a special case of
AudacityCommand and we'll split and rename the EffectManager class.

- Don't use 'default' as a parameter name.
- Massive renaming for CommandDefinitionInterface
- EffectIdentInterface becomes EffectDefinitionInterface
- EffectAutomationParameters becomes CommandAutomationParameters
- PluginType is now a bit field.

This way we can search for related types at the same time.

- Most old batch commands made into AudacityCommands.
The ones that weren't are for a reason.  They are used by mod-script-pipe
to carry commands and responses across from a non-GUI thread to the GUI
thread.

- Major tidy up of ScreenshotCommand
- Reworking of SelectCommand
- GetPreferenceCommand and SetPreferenceCommand
- GetTrackInfo and SetTrackInfo
- GetInfoCommand
- Help, Open, Save, Import and Export commands.
- Removed obsolete commands ExecMenu, GetProjectInfo and SetProjectInfo
  which are now better handled by other commands.

- JSONify "GetInfo: Commands" output, i.e. commas in the right places.

- General work on better Doxygen.
    - Lyrics -> LyricsPanel
    - Meter -> MeterPanel
- Updated Linux makefile.
- Scripting commands added into Extra menu.
- Distinct names for previously duplicated find-clipping parameters.
- Fixed longstanding error with erroneous status field number which
  previously caused an ASSERT in debug.
- Sensible formatting of numbers in Chains, 0.1 not 0.1000000000137

configure

@@ -2902,7 +2902,7 @@ ac_configure="$SHELL $ac_aux_dir/configure"  # Please don't use this var.
 
 
 
-am__api_version='1.15'
+am__api_version='1.14'
 
 # Find a good install program.  We prefer a C program (faster),
 # so one script is as good as another.  But avoid the broken or
@@ -3074,8 +3074,8 @@ test "$program_suffix" != NONE &&
 ac_script='s/[\\$]/&&/g;s/;s,x,x,$//'
 program_transform_name=`$as_echo "$program_transform_name" | sed "$ac_script"`
 
-# Expand $ac_aux_dir to an absolute path.
-am_aux_dir=`cd "$ac_aux_dir" && pwd`
+# expand $ac_aux_dir to an absolute path
+am_aux_dir=`cd $ac_aux_dir && pwd`
 
 if test x"${MISSING+set}" != xset; then
   case $am_aux_dir in
@@ -3094,7 +3094,7 @@ else
 $as_echo "$as_me: WARNING: 'missing' script is too old or missing" >&2;}
 fi
 
-if test x"${install_sh+set}" != xset; then
+if test x"${install_sh}" != xset; then
   case $am_aux_dir in
   *\ * | *\	*)
     install_sh="\${SHELL} '$am_aux_dir/install-sh'" ;;
@@ -3422,8 +3422,8 @@ MAKEINFO=${MAKEINFO-"${am_missing_run}makeinfo"}
 # <http://lists.gnu.org/archive/html/automake/2012-07/msg00014.html>
 mkdir_p='$(MKDIR_P)'
 
-# We need awk for the "check" target (and possibly the TAP driver).  The
-# system "awk" is bad on some platforms.
+# We need awk for the "check" target.  The system "awk" is bad on
+# some platforms.
 # Always define AMTAR for backward compatibility.  Yes, it's still used
 # in the wild :-(  We should find a proper way to deprecate it ...
 AMTAR='$${TAR-tar}'
@@ -3597,7 +3597,6 @@ END
   fi
 fi
 
-
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to enable maintainer-specific portions of Makefiles" >&5
 $as_echo_n "checking whether to enable maintainer-specific portions of Makefiles... " >&6; }
     # Check whether --enable-maintainer-mode was given.