split parameters for logging and tuning

add a flag to enable/disable tuning: default off
add an option for specifying a folder for outputting logs.

Closes: #10
Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I43864768f1dee8672f13288d3cf5a0c87c373aed
diff --git a/pid/tuning.cpp b/pid/tuning.cpp
index c3f21ed..3422e34 100644
--- a/pid/tuning.cpp
+++ b/pid/tuning.cpp
@@ -16,5 +16,7 @@
 
 #include <string>
 
-bool tuningLoggingEnabled = false;
-std::string tuningLoggingPath;
+bool tuningEnabled = false;
+
+std::string loggingPath;
+bool loggingEnabled = false;