Fixed docstring in synchronous serial client connect() method

I think there was a copy/paste error in the docstring. It said tcp but I think it is supposed to be serial.
(cherry picked from commit c7dae14)
Adding source_address to TCP client inputs
(cherry picked from commit c0ae343)
Typo
(cherry picked from commit 7d0d751)
Typo
(cherry picked from commit 233d437)
Typo
(cherry picked from commit eb8ee2e)
Typo
(cherry picked from commit 6cba334)
Adding some new examples

* modbus scraper (and documentation)
* thread safe datastore (and documentation)
(cherry picked from commit 66be36a)
Fixing the serial framers

- Adding new state machine for sync
- Async still uses stream interface
(cherry picked from commit 1a160e8)
Adding a concurrent client example
(cherry picked from commit a300002)
Allowing options to be passed through

- This fixes issue #21
- Options now go to the transaction manager
(cherry picked from commit 4d43643)