Update default History_Limit to 50
Update default History_Limit to 50

The default 100 is causing error when loading the wallet transactions history.

[error] Error: Error querying the blockchain
[Error: Error querying the blockchain]

This is BWS log showing the error:

WARN REQUEST FAIL: https://insight.bitpay.com:443/api/addrs/txs?from=0&to=100 STATUS CODE: 503
WARN Insight https://insight.bitpay.com:443/api/addrs/txs?from=0&to=100 Returned Status: 503
ERR! /v1/txhistory/?r=69638 :500:Error querying the blockchain
matiu/bitcore-wallet-service,bitjson/bitcore,martindale/bitcore,bitpay/bitcore,bitpay/bitcore-wallet-service,bitpay/bitcore,bitjson/bitcore,martindale/bitcore,bitpay/bitcore-wallet-service,troggy/bitcore-wallet-service,martindale/bitcore,janko33bd/bitcore-wallet-service,bitjson/bitcore,bitpay/bitcore,matiu/bitcore-wallet-service,martindale/bitcore,bitpay/bitcore,bitjson/bitcore,troggy/bitcore-wallet-service,janko33bd/bitcore-wallet-service