Dropped ios 5 and fixed warnings
Fixes #295

Updated OBASelectorJsonDigesterRuleTarget enum to use modern syntax
Updated the OBASelectorJsonDigesterRule.h to return instancetype & added a note explaining target memory paradigm

Simplified the implementation of OBASelectorJsonDigesterRule & replaced ivars with properties.    ivar by default maintains a strong reference, this was causing a retain cycle.
Adressed warnings shown by static analysis.
Merge pull request #298 from Wizecoder/drop-ios-5

Dropped ios 5 and fixed warnings
Merge pull request #296 from beliyd/dev/fix/issue-295

Fixes #295
Handle merge conflicts with PR297
Merge branch 'beliyd-dev/fix/warnings' into develop
Update CHANGELOG.md
Update version number