Rename timer `Setup` function to `Schedule`

This patch was motivated by my desire to fix a typo in the function
name. The noun "setup" is 1 word. The verb "set up" is 2 words. All
other member functions are verbs, so this one should be a verb too.
That means that the function should be called `SetUp`. During the
discussion that resulted from the rename, James Kuszmaul pointed out
that "setting up" a timer can be confusing. It implies that you can
only "set up" a timer once. But the intent is to let users set up
timers as many times as they like. So we decided on renaming the
function to `Schedule`. That conveys the purpose and intent better.

I took this opportunity to fix some other typos involving the verb
"set up".

Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
Change-Id: I2f557d1f946960af82711f248820d5e2d385a5d3
diff --git a/aos/events/ping_lib.cc b/aos/events/ping_lib.cc
index 8e7136d..a7a8dd4 100644
--- a/aos/events/ping_lib.cc
+++ b/aos/events/ping_lib.cc
@@ -25,8 +25,8 @@
   }
 
   event_loop_->OnRun([this]() {
-    timer_handle_->Setup(event_loop_->monotonic_now(),
-                         chrono::milliseconds(FLAGS_sleep_ms));
+    timer_handle_->Schedule(event_loop_->monotonic_now(),
+                            chrono::milliseconds(FLAGS_sleep_ms));
   });
 
   event_loop_->SetRuntimeRealtimePriority(5);