JFG-583
+ add period attribute to exact invocation load
JFG-583
add xsd docu for 'period' attribute.
JFG-583  max inaccuracy equals to tickInterval for test (not for one period)
+  notes in sendSamples method
+ warn message if load time more then period
+ load-invocation tests for smoke tests
merge commit
Merge pull request #364 from amikryukov/home-583

JFG-583