Use dynamic builds by default

Static builds are the special case, so it should be left off
by default.
diff --git a/cmake/StaticBuild.cmake b/cmake/StaticBuild.cmake
index 8f06a14..7679f45 100644
--- a/cmake/StaticBuild.cmake
+++ b/cmake/StaticBuild.cmake
@@ -8,7 +8,7 @@
 #
 
 option(BUILD_STATIC
-    "Link statically against most libraries, if possible" ON)
+    "Link statically against most libraries, if possible" OFF)
 
 if(BUILD_STATIC)
   message(STATUS "Attempting to link static binaries...")