Fixed spelling error in Database.java

Changed error message "Error occured while trying to connect to the database" to "Error occurred while trying to connect to the database"
[DOC] BACKLOG-1314 - Document the REST calls for Carte (Kettle Path) Part2

What was done:
1) added JMeter tests for the servlets required
2) added comments to the classes
[DOC] BACKLOG-1176 -- Document the REST calls for Carte (Kettle Path) (Part 1)

What was done:
1) changed wording according to Chantel's review
Merge pull request #858 from kolinus/BACKLOG-1176-1

[DOC] BACKLOG-1176 -- Document the REST calls for Carte (Kettle Path) (P...
[PDI-12947] one connection pool created per step
[PDI-13049] - Regression: PDI 5.1 Clone Rows NULLs
Merge pull request #856 from SergeyTravin/PDI-12947

[PDI-12947] one connection pool created per step
Merge pull request #861 from akhayrutdinov/PDI-13049

[PDI-13049] - Regression: PDI 5.1 Clone Rows NULLs
Merge pull request #859 from kolinus/BACKLOG-1314

[DOC] BACKLOG-1314 - Document the REST calls for Carte (Kettle Path) Par...
BACKLOG-1314 -- Document the REST calls for Carte (Kettle Path) (Part 2)

What was done:
1) uncommented JMeter tests
2) changed comments according to Chantel notes.
[BACKLOG-1479]: Implement support for Carte parameters (threads and connections)

Implement necessary code changes to support configuring the following options for Carte:
acceptors, acceptQueueSize, lowResourcesMaxIdleTime.
lowResourcesConnections option is not supported by org.mortbay.jetty.bio.SocketConnector that is used in the current implementation of Carte web server so it's out of scope.
Also there are unit tests.
Merge pull request #866 from kolinus/BACKLOG-1314

[DOC] BACKLOG-1314 -- Document the REST calls for Carte (Kettle Path) (Part 2)
[TEST] Fix deprecated Date methods in ValueMetaTest
Merge pull request #867 from TatsianaKasiankova/BACKLOG-1479

[BACKLOG-1479]: Implement support for Carte parameters (threads and connections)
Merge pull request #868 from mattyb149/test

[TEST] Fix deprecated Date methods in ValueMetaTest
PDI-11968 - PDI - Carte Cluster does not work. New cluster does not show up to be selected
PDI-12948 - deadlock when mixing pooled and non-pooled connections
Merge pull request #863 from SergeyTravin/PDI-12948

PDI-12948 - deadlock when mixing pooled and non-pooled connections
Merge pull request #832 from levyj/master

CLEANUP: Fixed spelling error in Database.java
[PDI-13279]: Pass correct object from JobEntryJobRunner to extension points