remove compilerLib, move contents into libTheory
move some theorems from compiler/proofs to semantics/proofs
remove unused repl/repl_compute* stuff
add install-deps script and travis.yml config

experiment with continuous integration.
probably doomed to failure since they have a hard limit of 50 minutes
and we have to build HOL before even starting a build.
pushd and popd require bash
missed a level of polyml's directory nesting
set PATH for the regression test

also tweak regression test to fail if it can't execute heapname (which
would be evidence that HOL's bin directory isn't in the path or HOL
isn't built).
also need to set LD_LIBRARY_PATH for build
try to get better output from travis builds
revert attempt to quiet bin/build by hand

didn't work properly on travis, not worth fixing
Merge remote-tracking branch 'origin/master' into init_env

Conflicts:
	compiler/compilerLib.lem
	compiler/compilerLibScript.sml
	standalone/cakeml_computeLib.sml