Fix issue #58 independent make file

It would be easier to review each change-set separately:

Read `redcap_uri` and `token` from settings.ini …	13d8ff4
Define `REDCAP_PROJECT_ID` value in `Makefile.ini` ...	c691cc8
Define `REDCAP_PROJECT_FORMS` to be used by `rc_get` task ...  463a07b
Remove references to `demographics` …	a46e5f7
Remove redundant json file: `vagrant-data/demographic_test_data.json` …	0d76612
Add filter: grep -v '^\#' to skip comments when parsing the ini file ...	a06abdc
Add `vagrant/Makefile.ini` to the list of ignored files …	cc39b61
Small cleanup of the help strings	... 2ae39fc
Add new makefile task `rc_compare` to help comparison with the reference file ... ceb4e36