erlang-eimp: Update to 1.0.18

upstream changes:
-----------------
Version 1.0.18
  * Updating p1_utils to version 1.0.21.
  * Load external libraries dynamically

Version 1.0.17
  * Updating p1_utils to version 1.0.20.

Version 1.0.16
  * Add Travis and support for Erlang/OTP 23.0

Version 1.0.15
  * Updating p1_utils to version 1.0.19.
  * Fix compatibility issues with Erlang 23

Version 1.0.14
  * Updating p1_utils to version 1.0.18.
  * Update copyright year
  * Don't assume that image libs are available when configure was not called

Version 1.0.13
  * Updating p1_utils to version 1.0.17.

Version 1.0.12
  * Updating p1_utils to version 1.0.16.
  * Update type specs

Version 1.0.11
  * Updating p1_utils to version 1.0.15.

Version 1.0.10
  * Updating p1_utils to version 1.0.14.
  * Add contribution guide

Version 1.0.9
  * Include configure and vars.config.in in hex package

Version 1.0.8
  * Updating p1_utils to version 1.0.13.

Version 1.0.7
  * Updating p1_utils to version 6ff85e8.
  * Pack rebar.config.script in hex package

(triaxx)