[BACKLOG-175]: A corrupt repository object leaves the repository explorer in an unusable state.

There is an issue in JCR: NPE when calling node.getBaseVersion()(please see https://issues.apache.org/jira/browse/JCR-2382)
So the fix consists of catching NPE from JRC, logging the error and returnig null value for Version.
Also added several unit tests.
PPP-3308 - Migration Tool does not migrate double byte files and folders

What was done:
1) changed path encode and decode routines to encode invalid symbols
2) added id encode routine as it was called once but id may start with
digit which is not valid for path anymore
3) added unit tests  to validate different usage of routines
[BISERVER-11584] - Data source created via Data Source Wizard on one cluster node is not visible on the other nodes

make CacheKey serializable
make "metadata-domain-repository" and "mondrian-catalog-cache" distributable
[BACKLOG-116] Fix divider colors in popovers
[BACKLOG-194] Fixed a bug in the /repo/files/{pathId : .+}/children endpoint
Merge pull request #1914 from AlexanderBuloichik/BACKLOG-116c

[BACKLOG-116] Fix divider colors in popovers
Merge pull request #1915 from bmorrise/dev

[BACKLOG-194] Fixed a bug in the /repo/files/{pathId : .+}/children endp...
[BISERVER-11819] - Cannot Add to favorite a file with special characters from the Recents list
Merge pull request #1815 from aliakseihaidukou/BISERVER-11584

[BISERVER-11584] - Data source created via Data Source Wizard on one clu...
Merge pull request #1774 from kolinus/PPP-3308

PPP-3308 - Migration Tool does not migrate double byte files and folders
Merge pull request #1724 from TatsianaKasiankova/BACKLOG-175

[BACKLOG-175]: A corrupt repository object leaves the repository explorer in an unusable state.
Merge pull request #1799 from apratkin/BACKLOG-363

[BISERVER-11819] - Cannot Add to favorite a file with special characters...