Spelling fixes

Spelling errors found using github.com/lucasdemarchi/codespell
A tool to fix common misspellings.
This tool is licensed under GNU General Public License, version 2.

Change-Id: Ib95e14205fe5fa72c27f35305c822234052420ef
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/events.hpp b/events.hpp
index 38c24e4..a6e3a5d 100644
--- a/events.hpp
+++ b/events.hpp
@@ -14,7 +14,7 @@
 /** @struct Event
  *  @brief Event object interface.
  *
- *  The event base is an assocation of an event type
+ *  The event base is an association of an event type
  *  and an array of filter callbacks.
  */
 struct Event : public std::vector<Filter>