Blynk cleanup

[mcspr]

As mentioned in xoseperez#1230

This is general clean-up + some things I had noticed while reading blynk library code. I did a test with sensors board + dummy relay and it did work, so I don't think i had missed anything.

Reword VPin explanation in WebUI
Backoff timer for connection
Overridable defines
Test as travisN device (compilation test depends on BLYNK_SUPPORT enabled)
Some types and naming clean-up (unsigned -> uint, blnk methods -> blynk, blnkAuthKey -> blnkToken etc...)
Adapted BlynkWifi class from Blynk library and overridable funcs instead of tracking WiFiClient

[thaeger71]

so far I know, blynk library does support only 128 VPins at max. And another question is, what if all default values are 0 and only one magnitude is set to a proper Vpin ? Then all others will be assigned to VPin 0 ....

[mcspr]

Yes, I had noticed the range you had was different from app. And I did test with pins like 140,141 etc. Plus, see internal object used as request param in writer (it is uint8_t limit essentially):
https://github.com/blynkkk/blynk-library/blob/5e84887060ef9cb4da5b64d8386689741af0d78f/src/Blynk/BlynkHandlers.h#L211-L214

You think it should check vpins uniqueness in web?
It stops searching on the first match, both relays and sensors. So having 0 as value for blnkMagnitude0,1,2,3... will sure send everything to vpin0, but only trigger the first relay found when asked to match vpin<->relays backwards. And it checks a-la hasSetting for key existence and value lengths beforehand - this is what i did instead of using -1 as default.