add encoding rule (#157)

[TristanFAURE]

cf my question this pull request adds the encoding rule : https://palantir.github.io/tslint/rules/encoding/

did a mvn clean test and result was OK

[coveralls]

Coverage remained the same at 92.018% when pulling e5a9261 on TristanFAURE:master into 18ba6ad on Pablissimo:master.

[TristanFAURE]

hello, do you plan to integrate this PR ? or do you want me to do some updates ?

[Pablissimo]

I'm just struggling for time @TristanFAURE - aiming to find a couple hours this weekend

[TristanFAURE]

Thank you for this feedback, no problem it was just a friendly reminder