core/net/uip.h: Add missing #include <string.h>

Fixes implicit definition of memcmp() warnings/errors.

Signed-off-by: Joakim Gebart <joakim.gebart@eistec.se>
Merge pull request #711 from gebart/upstream-fix-implicit-definitions

uip.h missing #include <string.h>
Merges Z1SP into Z1 platform
Only wait for a keypress if the user is told to press a key.
Merge pull request #747 from oliverschmidt/master

Only wait for a keypress if the user is told to press a key.
Merge pull request #739 from alignan/merge_z1sp_with_z1

Merges Z1SP into Z1 platform
Clean up script commands in .travis.yml.

Besides general whitespace and quoting cleanup, commands that test
variables were changed from:
  [ $B = a ] && command || true
to
  if [ $B = a ] ; then command ; fi
This form correctly returns the exit code of "command".
Add "travis_retry" to commands that download from external servers.

This helps reduce the chance of a build failure due to transient
download error.
Rename travis "arm" BUILD_ARCH to "arm-apcs".

These platforms are built with an old ARM compiler that supports the
deprecated APCS standard.