Fixed writing to the Channel object when no member value coercion was required. (#1176)

* Updated documentation for encode functions to accurately describe return values (0 on error instead of BACNET_STATUS_ERROR)

* Expanded property support, removed INPUT object types, added fallback encoding for non-coerced data types, and updated error handling in ReadProperty of present-value to check for 0 instead of BACNET_STATUS_ERROR.

* Expanded the validation tests and increased test code coverage.

test/bacnet/basic/object/channel/CMakeLists.txt

@@ -23,6 +23,7 @@ set(ZTST_DIR "${TST_DIR}/ztest/src")
 add_compile_definitions(
     BIG_ENDIAN=0
     CONFIG_ZTEST=1
+    CHANNEL_MEMBERS_MAX=16
     )
 
 include_directories(