Make rebar no longer be necessary to run Makefile

We check if there is a rebar, if so we use, otherwise we don't. This
means that some commands are no longer possible. We should probably
remove some of them anyway.
merge
merge in tests from master branch
Add in send and recieve code

Fix #47
Add copyright and licence
Merge tests
added test for display/1 and test and code for display/2
added nl/0
Combine interpreter state variables into state record #est

This is mainly just to make handling of them easier and not so much
for hiding internal fields which are explicitly accessed when
necessary. It will also make it easier to add new fields when
necessary.
Make it work for loading files as well
Fix error handling to use state and use try/catch instead of catch
Convert ets interface to new state record
Make sure findall drops all new bindings and revert to old bindings

Fixes #50.
Update tests for new code
fix a test
add path to eqc
Merge branch 'develop' into swi_io
Merge branch 'master' into swi_io