PDI-11979 - Junits tests

Added junit test based on load/save framework.
PDI-11979 - Fieldnames in the "Execution results" tab of the Job executor step saved incorrectly in repository

added simple fix to loadRepository method.
[PDI-11439] SimpleTimestampFormatter with unit tests
[PDI-11439] Oracle Bulk loader failing for timestamp with sixth precision column
Merge pull request #473 from prakapenka/PDI-11979

PDI-11979 - Fieldnames in the "Execution results" tab of the Job executor step saved incorrectly in repository
Merge pull request #449 from stepanovdg/PDI-11439

[PDI-11439] Oracle Bulk loader failing for timestamp with sixth precision column
PDI-7923 - integration test added
PDI-7923 - Formula step requires Number value type when could be used Integer

Added ability to guess Kettle ValueMeta for any Object.
Added ability to Formula step convert calculation result to target output
ValueMeta.
When we achieve formula calculation result as erased Object type we trying
to guess kettle value meta for this type, and convert it to target value
meta.
To reduce perfomance impact we also trying to discover is this conversion
is really necessary. If input value meta is suitable for formula
calculation result we skip conversion and just pass value to next step
signed by output value meta (which was cloned from input value meta).