Upgrade Mercury. Fix retry

Changed

• Upgrade mercury version. Use mercury "sources" methods from "apis" methods. Keep "apis" methods due to retrocompatibility.
• Downgrade axios minor version to 0.18.0 until axios-retry fix issue softonic/axios-retry#59

Fixed

• Fix "retry" option.

Upgrade dependencies

Changed

• Upgrade mercury version

Multiple apis configurator

• Add apis method, which allows to configure, manage headers or clean multiple apis at a time. Groups of apis can be defined using new config property called tags.

Fix Axios vulnerability

Fixed

• Upgrade Axios dependency to fix a potential vulnerability.
• Fix events unit test.

First public release

• Forked from xByOrange reactive-data-source v1.7.0 library. (Only origins.Api is exposed from now)
• Extends from Mercury Origin instead of reactive-data-source origin. (Refer to mercury CHANLEGOG for further details)
• Removed methods option. Now constructor accepts only two arguments.