1.0.3

added `CNMI` command to init function

I had problems when using the `CMGL` command and it wouldn't reply with any message in the buffer, adding the CNMI configuration in the init solved the issue for me

1.0.2

chang log:

• Fixed bug in isCallActive functionality.
• Add functionality sim900_read_string_until

1.0.1

Increase sendSMS timeout parameters to fix false report Send SMS failed!