Merge/fs3 14980 visitor identifier warning (#13)

* Fixed:
- Warning on visitor creation

Fix/fs3 bd002 json pkg (#12)

Changed: org.json dependency upgraded

Fix/fs3 bd001 java 8 (#11)

Merge publish on maven central

Fs3 542 event value type (#7)

Fix Event hit value type: must be integer > 0

Fs3 370 slug (#4)

### [3.0.3 (Latest version)](doc:android-v3)
* Added campaign slug information in FlagMetadata

Update README.md

fix readme.md content

Fs3 291 fix bucketing realloc 2 (#2)

#### Fixed
* Prevention of variation reallocation in Bucketing mode.
* Offline flag management have been fixed in Bucketing mode.

#### Added
* VariationGroup and Variation ids assignations history have been added in IVisitorCacheImplementation cache lookup format.

update README

release 1.0.0