tools/create

Possible solution for the first FIXME

Tries to get the HEAD of the workshop page URL, if it succeeds (i.e. it already exists), retuns an error and exits
Switch from SSH to HTTPS cloning
Fix build problems for ubuntu 14.04
Polish text
Check that repository was successfully cloned

Close #25
quoting INSTRUCTORS solves problem of collaborators being added and
Bringing local copy up to date.

Merge remote-tracking branch 'upstream/gh-pages' into gh-pages
Simplifying Markdown files even further.

1. Tidied up wording in README.md.
2. Took background and design discussion out of CUSTOMIZATION.md and put it into DESIGN.md.
Merge pull request #16 from tpoisot/patch-1

tools/create
Merging #1 from @DamienIrving manually
Merging #26 manually
Merge pull request #30 from r-gaia-cs/verify-clone

Check that repository was successfully cloned
Fix build problems for ubuntu 14.04
Polish text
Adding instructions to install the Python YAML module (resolves #15)
Merge pull request #34 from drlabratory/gh-pages

Quote INSTRUCTORS in tools/create
Merging in changes from gh-pages
Merge pull request #35 from gvwilson/tidying-up-wording

Simplifying Markdown files even further.
Removing FIXME markers from head of file