T3100
This diff updates the Send.js screen to enforce the unencrypted OP_RETURN message limit via byte size rather than char size. This utilizes the maximum OP_RETURN limit (OP_RETURN uses bytesize) and increases unencrypted message length to 215 bytes.
Fee calculation logic is also updated in this diff to take into account OP_RETURN bytesize. This could not be split into a separate diff otherwise the new bytesize parsed OP_RETURN txs will be rejected by bitcoind on account of incorrect tx fee.
The fee calc logic for token creation will be addressed in the next diff to avoid bloating this diff. It is expected to not work in this particular diff given changes to `calcFee`.
Updated Unit tests for `getMessageByteSize`, `calcFee` and `generateTxInput`.
**Note:** Subsequent diffs planned in this stack:
- [Cashtab] [OP_RETURN msg upgrade] - Pt2 - Use bytecount for token creation/sends
- [Cashtab] [OP_RETURN msg upgrade] - Pt3 - Use bytecount for unencrypted airdrop messages
- [Cashtab] [OP_RETURN msg upgrade] - Pt4 - Use bytecount for encrypted messages
- [Cashtab] [OP_RETURN msg upgrade] - Pt5 - Use of compressEpk in ECIES encryption mechanism to reduce encryption bytes used in OP_RETURN output