Update lang/erlang* to 19.1.

Some highlights of the release are:

- erts: Improved dirty scheduler support. A purge of a module will
- not have to wait for completion of all ongoing dirty NIF calls.
- erts: Improved accuracy of timeouts on MacOS X.
- kernel: Add net_kernel:setopts/2 and net_kernel:getopts/2 to
- control options for distribution sockets in runtime.
- asn1: Compiling multiple ASN.1 modules in the same directory with
- parallel make (make -j) should now be safe.
- httpd: support for PUT and DELETE in mod_esi
- ~30 contributions since 19.0

You can find the Release Notes with more detailed info at

http://www.erlang.org/download/otp_src_19.1.readme

(fhajny)