build: don't let libtool insert rpath into binaries
build: Find the proper xcb/pcre dependencies
build: add WIP dependency builder.

This is in constant flux and is not ready for any real use.
travis: initial config
gitian: replace descriptors
travis: use beta builder with cache enabled

Linux only for now, since sudo can't be used
add native comparison tool
travis: redirect comparison tool output to stdout

Otherwise travis thinks the build has stalled.
run tests