PDI-10467 - Data Grid step: Meta tab values for all columns get lost upon going to Data tab.

What was done:
1) Removed extra method call
PDI-10828 - Variables in Commit Size for Update, Insert/Update and Delete
Steps are not accepted

What was done:
1)changed Meta classes to support string value
2) changed step classes to convert string to value with respect to
variables
3) changed dialog classes to avoid unnecessary convertions
4) added unit tests
PDI-10828 - Variables in Commit Size for Update, Insert/Update and Delete
Steps are not accepted

UI changes to mark fields that they support variables
PDI-10828 - Variables in Commit Size for Update, Insert/Update and Delete Steps are not accepted

What was done:
1) changed the way bug is fixed according to Matt Burgess's notes
2) added backward compatibility support
PDI-9937 - As an ETL developer, I'd like the check if a folder is empty step short-circuit as soon as a file is found

What was done:
1) added a new exception type
2) changed the way iteration is done in TextFileSelector (Kettle source files)
3) added a new exception handling logic
[PDI-7564] HTTP Client logs Status 204 as an error (204: No Content)
PDI-10936 - add unit test and use JUnit4
PDI-10936 return false if processRow input is empty
[PDI-10936] Apply formatting and adding JUnit4 wrapper
PDI-689 - Copy / paste of steps doesn't copy error handling information
[PDI-7374] PDI REST Client should not log a status 204 as an error.
PDI-10862 - Synchronized stepListeners collection
Merge pull request #154 from kolinus/PDI-10467

PDI-10467 - Data Grid step: Meta tab values for all columns get lost upo...
Merge pull request #158 from kolinus/PDI-10828-2

Pdi 10828 - Variables in Commit Size for Update, Insert/Update and Delete Steps are not accepted
Merge pull request #165 from hudak/PDI-10862

PDI-10862 - Synchronized stepListeners collection
Merge pull request #164 from stepanovdg/PDI-7374

[PDI-7374] PDI REST Client should not log a status 204 as an error.
Merge pull request #163 from pavel-sakun/PDI-689

PDI-689 - Copy / paste of steps doesn't copy error handling information
PDI-10764 - Fail on importing from existing ktr file while using oracle db as repository.

The problem is that column type for oracle is CLOB, but the column is used
in where sectio of queries as a normal varchar2 whhich does not work.
So I changed the code creating repository to limit NAMESPACE NAME to 2000
charatcers instead of 2000

What was done:
1) changed the way we init the repository
2) implemented getMaxVARCHARLength() for Oracle and MSSQL
3) changed implementation of corresponding getFieldDefinition methods to
use member getter instead of hardcoded value

What was done later:
1) changed the way we select type length
Refactor the class to allow unit testing
[PDI-9815] Show appropriate err msg if technical key is null