new buildSchedule function and tests for string parsing

CHANGELOG.md

@@ -13,7 +13,11 @@
     * Kotlin `1.3.70` -> `1.3.72`
     * Coroutines `1.3.5` -> `1.3.7`
     * Klock `1.10.0` -> `1.11.3`
+* A lot of KDocs added and fixed
 * `EverySecondScheduler` changed its building logic - now it is lazy with builder using
+* `KronScheduler#doOnce` was optimized: now it will be explicitly called once and return result of its calculations
+    * `KronScheduler#doWhile` was rewritten to use `KronScheduler#doOnce` for calculations of `block` result
+* New `buildSchedule(String)` function as a shortcut for `createSimpleScheduler(String)`
 
 ### 0.2.2